{"id":"CVE-2026-45066","aliases":["DEBIAN-CVE-2026-45066","EUVD-2026-44339","GHSA-qc95-4862-92fh","UBUNTU-CVE-2026-45066"],"status":"published","title":"Symfony: HtmlSanitizer allowLinkHosts() / allowMediaHosts() Bypass via URL-Parser Differentials and \u003carea\u003e Misclassification","description":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because \u003carea href\u003e is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.","severity":{"version":"4.0","score":2.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00338,"percentile":0.27572,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-184","CWE-436"],"published":"2026-05-27T20:13:04Z","modified":"2026-10-28T02:30:43Z","fixes":[{"ecosystem":"Packagist","package":"symfony/html-sanitizer","fixed_in":["6.4.40","7.4.12","8.0.12"],"sources":["ghsa","osv"]},{"ecosystem":"Packagist","package":"symfony/symfony","fixed_in":["6.4.40","7.4.12","8.0.12"],"sources":["ghsa","osv"]},{"ecosystem":"Debian:13","package":"symfony","fixed_in":["6.4.41+dfsg-0+deb13u1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"symfony","fixed_in":["7.4.12+dfsg-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"symfony/html-sanitizer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.0"},{"fixed":"6.4.40"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"symfony/html-sanitizer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.4.12"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"symfony/html-sanitizer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.12"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"symfony/symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.0"},{"fixed":"6.4.40"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"symfony/symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.4.12"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"symfony/symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.12"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.4.41+dfsg-0+deb13u1"}]}],"versions":["6.4.21+dfsg-2","6.4.21+dfsg-2+deb13u1","6.4.24+dfsg-1","6.4.25+dfsg-1","6.4.40+dfsg-0+deb13u1"]},{"source":"osv","ecosystem":"Debian:14","package":"symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.4.12+dfsg-1"}]}],"versions":["6.4.21+dfsg-2","6.4.24+dfsg-1","6.4.25+dfsg-1","7.0.4+dfsg-1","7.0.5+dfsg-1","7.0.6+dfsg-1","7.0.7+dfsg-1","7.1.0~beta1+dfsg-1","7.1.0~rc1+dfsg-1","7.1.2+dfsg-1","7.1.3+dfsg-1","7.1.4+dfsg-1","7.1.5+dfsg-1","7.2.0~beta1+dfsg-1","7.2.0~beta2+dfsg-1","7.2.0~rc1+dfsg-1","7.2.1+dfsg-1","7.2.2+dfsg-1","7.2.3+dfsg-1","7.2.4+dfsg-1","7.2.5+dfsg-1","7.2.6-1","7.3.0+dfsg-1","7.3.0~beta1+dfsg-1","7.3.0~beta2+dfsg-1","7.3.0~rc1+dfsg-1","7.3.1+dfsg-1","7.3.2+dfsg-1","7.3.3+dfsg-1","7.3.4+dfsg-1","7.3.5-1","7.4.0+dfsg-1","7.4.0+dfsg-2","7.4.0~beta1-1","7.4.0~beta1-2","7.4.0~beta2+dfsg-1","7.4.0~beta2+dfsg-2","7.4.0~beta2+dfsg-3","7.4.0~rc1+dfsg-1","7.4.0~rc2+dfsg-1","7.4.0~rc3+dfsg-1","7.4.10+dfsg-1","7.4.2+dfsg-1","7.4.2+dfsg-2","7.4.3+dfsg-1","7.4.4+dfsg-1","7.4.5+dfsg-1","7.4.6+dfsg-1","7.4.6+dfsg-2","7.4.7+dfsg-1","7.4.8+dfsg-1","7.4.9+dfsg-1"]},{"source":"osv","ecosystem":"Packagist","package":"symfony/html-sanitizer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.0"},{"fixed":"6.4.40"}]}],"versions":["v6.1.0","v6.1.11","v6.1.9","v6.2.0","v6.2.0-BETA1","v6.2.0-RC1","v6.2.2","v6.2.5","v6.2.7","v6.3.0","v6.3.0-BETA1","v6.3.0-RC1","v6.3.12","v6.3.4","v6.3.7","v6.4.0","v6.4.0-BETA1","v6.4.0-BETA2","v6.4.0-RC1","v6.4.12","v6.4.13","v6.4.17","v6.4.18","v6.4.21","v6.4.24","v6.4.25","v6.4.28","v6.4.3","v6.4.35","v6.4.4","v6.4.7","v6.4.8"]},{"source":"osv","ecosystem":"Packagist","package":"symfony/html-sanitizer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.4.12"}]}],"versions":["v7.0.0","v7.0.3","v7.0.4","v7.0.7","v7.0.8","v7.1.0","v7.1.0-BETA1","v7.1.0-RC1","v7.1.1","v7.1.10","v7.1.11","v7.1.5","v7.1.6","v7.2.0","v7.2.0-BETA1","v7.2.0-RC1","v7.2.2","v7.2.3","v7.2.6","v7.2.9","v7.3.0","v7.3.0-BETA1","v7.3.0-RC1","v7.3.2","v7.3.3","v7.3.6","v7.4.0","v7.4.0-BETA1","v7.4.0-BETA2","v7.4.0-RC1","v7.4.7","v7.4.8"]},{"source":"osv","ecosystem":"Packagist","package":"symfony/html-sanitizer","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.12"}]}],"versions":["v8.0.0","v8.0.7","v8.0.8"]},{"source":"osv","ecosystem":"Packagist","package":"symfony/symfony","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.1.0"},{"fixed":"6.4.40"}]}],"versions":["v6.1.0","v6.1.1","v6.1.10","v6.1.11","v6.1.12","v6.1.2","v6.1.3","v6.1.4","v6.1.5","v6.1.6","v6.1.7","v6.1.8","v6.1.9","v6.2.0","v6.2.0-BETA1","v6.2.0-BETA2","v6.2.0-BETA3","v6.2.0-RC1","v6.2.0-RC2","v6.2.1","v6.2.10","v6.2.11","v6.2.12","v6.2.13","v6.2.14","v6.2.2","v6.2.3","v6.2.4","v6.2.5","v6.2.6","v6.2.7","v6.2.8","v6.2.9","v6.3.0","v6.3.0-BETA1","v6.3.0-BETA2","v6.3.0-BETA3","v6.3.0-RC1","v6.3.0-RC2","v6.3.1","v6.3.10","v6.3.11","v6.3.12","v6.3.2","v6.3.3","v6.3.4","v6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Advisory","advisory","web"]},{"url":"https://github.com/symfony/symfony/commit/d506b556d3d3906f3e8660ad82257ce87edbaac4","tags":["x_refsource_MISC","Patch","fix"]},{"url":"https://github.com/symfony/symfony/releases/tag/v6.4.40","tags":["x_refsource_MISC","Product","Release Notes","web"]},{"url":"https://github.com/symfony/symfony/releases/tag/v7.4.12","tags":["x_refsource_MISC","Product","Release Notes","web"]},{"url":"https://github.com/symfony/symfony/releases/tag/v8.0.12","tags":["x_refsource_MISC","Product","Release Notes","web"]},{"url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/html-sanitizer/CVE-2026-45066.yaml","tags":["web"]},{"url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2026-45066.yaml","tags":["web"]},{"url":"https://symfony.com/cve-2026-45066","tags":["web"]},{"url":"https://github.com/advisories/GHSA-qc95-4862-92fh"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45066.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45066","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-45066","tags":["advisory"]},{"url":"https://github.com/symfony/symfony","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-45066","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-45066","tags":["report"]},{"url":"https://symfony.com/blog/cve-2026-45066-htmlsanitizer-allowlinkhosts-allowmediahosts-bypass-via-url-parser-differentials-and-area-misclassification","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-45066","title":"Symfony: HtmlSanitizer allowLinkHosts() / allowMediaHosts() Bypass via URL-Parser Differentials and \u003carea\u003e Misclassification","description":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because \u003carea href\u003e is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.","status":"published","published":"2026-07-14T17:53:49.836Z","modified":"2026-07-16T14:29:30.033Z","cvss":[{"version":"4.0","score":2.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low","assessor":"cna"}],"cwes":["CWE-184","CWE-436"],"updated_at":"2026-11-02T13:46:32.755125Z"}],"euvd":[{"id":"EUVD-2026-44339","description":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because \u003carea href\u003e is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.","status":"published","published":"2026-07-14T17:53:49Z","modified":"2026-07-16T14:29:30Z","cvss":[{"version":"4.0","score":2.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low"}],"updated_at":"2026-11-02T18:19:51.881225Z"}],"ghsa":[{"id":"GHSA-qc95-4862-92fh","title":"Symfony has an HtmlSanitizer allowLinkHosts() / allowMediaHosts() Bypass via URL-Parser Differentials and \u003carea\u003e Misclassification","description":"### Description\n\n`symfony/html-sanitizer` lets applications sanitise untrusted HTML. The configuration methods `allowLinkHosts([...])` and `allowLinkSchemes([...])` are intended to restrict `\u003ca href\u003e` targets to an allowlist of hosts/schemes; `allowMediaHosts()` / `allowMediaSchemes()` do the same for `\u003cimg src\u003e` etc.\n\nThree distinct bypasses allow a content author to smuggle off-allowlist URLs past these checks. First, `UrlSanitizer::parse()` parses the input following RFC-3986, while browsers follow the WHATWG URL Standard which normalises `\\` to `/` before parsing the authority of \"special\" schemes; so an input like `https://evil\\@trusted.com/` parses with host `trusted.com` server-side but navigates to `https://evil/` in the browser. Second, WHATWG collapses any run of `/` after the scheme into `//`, while RFC-3986 does not; so `https:/evil.com/` and `https:///evil.com/` parse as host-less (skipping the host allowlist) but resolve to `evil.com` in the browser. Third, `UrlAttributeSanitizer` checks `'a' === $element` to route to the link policy and falls through to the media policy otherwise, but `\u003carea\u003e` is a navigable hyperlink equivalent to `\u003ca\u003e`; so `\u003carea href\u003e` was sanitised against the media policy (which typically allows `data:` and may have no host allowlist), bypassing `allowLinkHosts()` / `allowLinkSchemes()` entirely.\n\n### Resolution\n\n`UrlSanitizer::sanitize()` now rejects URLs that contain a backslash or that use a special scheme (`http`, `https`, `ftp`, `ws`, `wss`) followed by a single slash or three slashes before parsing, eliminating the parser-differential bypasses. `UrlAttributeSanitizer` now applies the link policy to both `\u003ca\u003e` and `\u003carea\u003e` elements.\n\nThe patch for this issue is available [here](https://github.com/symfony/symfony/commit/d506b556d3d3906f3e8660ad82257ce87edbaac4) for branch 5.4.\n\n### Credits\n\nSymfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.","status":"published","published":"2026-05-27T20:13:04Z","modified":"2026-05-27T20:13:05Z","cwes":["CWE-184","CWE-436"],"updated_at":"2026-11-02T14:40:14.666177Z"}],"nvd":[{"id":"CVE-2026-45066","description":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because \u003carea href\u003e is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.","status":"published","published":"2026-07-14T18:17:16.703Z","modified":"2026-07-16T15:16:31.367Z","cvss":[{"version":"4.0","score":2.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"low","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-184","CWE-436"],"updated_at":"2026-11-02T14:12:29.489525Z"}],"osv":[{"id":"CVE-2026-45066","title":"Symfony: HtmlSanitizer allowLinkHosts() / allowMediaHosts() Bypass via URL-Parser Differentials and \u003carea\u003e Misclassification","description":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because \u003carea href\u003e is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.","status":"published","published":"2026-07-14T17:53:49.836Z","modified":"2026-10-28T02:30:43.403691775Z","cvss":[{"version":"4.0","score":2.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low"}],"cwes":["CWE-184","CWE-436"],"updated_at":"2026-11-02T15:45:05.172514Z"},{"id":"DEBIAN-CVE-2026-45066","description":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because \u003carea href\u003e is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.","status":"published","published":"2026-07-14T18:17:16.703Z","modified":"2026-10-01T03:03:14.575079488Z","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":"UBUNTU-CVE-2026-45066","description":"Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because \u003carea href\u003e is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.","status":"published","published":"2026-07-14T18:17:00Z","modified":"2026-10-17T13:00:10.946611979Z","cvss":[{"version":"4.0","score":2.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"low"},{"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":"2026-11-02T16:56:26.396868Z"},{"id":"GHSA-qc95-4862-92fh","title":"Symfony has an HtmlSanitizer allowLinkHosts() / allowMediaHosts() Bypass via URL-Parser Differentials and \u003carea\u003e Misclassification","description":"### Description\n\n`symfony/html-sanitizer` lets applications sanitise untrusted HTML. The configuration methods `allowLinkHosts([...])` and `allowLinkSchemes([...])` are intended to restrict `\u003ca href\u003e` targets to an allowlist of hosts/schemes; `allowMediaHosts()` / `allowMediaSchemes()` do the same for `\u003cimg src\u003e` etc.\n\nThree distinct bypasses allow a content author to smuggle off-allowlist URLs past these checks. First, `UrlSanitizer::parse()` parses the input following RFC-3986, while browsers follow the WHATWG URL Standard which normalises `\\` to `/` before parsing the authority of \"special\" schemes; so an input like `https://evil\\@trusted.com/` parses with host `trusted.com` server-side but navigates to `https://evil/` in the browser. Second, WHATWG collapses any run of `/` after the scheme into `//`, while RFC-3986 does not; so `https:/evil.com/` and `https:///evil.com/` parse as host-less (skipping the host allowlist) but resolve to `evil.com` in the browser. Third, `UrlAttributeSanitizer` checks `'a' === $element` to route to the link policy and falls through to the media policy otherwise, but `\u003carea\u003e` is a navigable hyperlink equivalent to `\u003ca\u003e`; so `\u003carea href\u003e` was sanitised against the media policy (which typically allows `data:` and may have no host allowlist), bypassing `allowLinkHosts()` / `allowLinkSchemes()` entirely.\n\n### Resolution\n\n`UrlSanitizer::sanitize()` now rejects URLs that contain a backslash or that use a special scheme (`http`, `https`, `ftp`, `ws`, `wss`) followed by a single slash or three slashes before parsing, eliminating the parser-differential bypasses. `UrlAttributeSanitizer` now applies the link policy to both `\u003ca\u003e` and `\u003carea\u003e` elements.\n\nThe patch for this issue is available [here](https://github.com/symfony/symfony/commit/d506b556d3d3906f3e8660ad82257ce87edbaac4) for branch 5.4.\n\n### Credits\n\nSymfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.","status":"published","published":"2026-05-27T20:13:04Z","modified":"2026-09-10T03:50:47.394247065Z","cwes":["CWE-184","CWE-436"],"updated_at":"2026-11-02T15:46:54.40888Z"}]}}