{"id":"CVE-2023-6992","aliases":["ALPINE-CVE-2023-6992","AZL-43663","AZL-43807","AZL-43870","AZL-43957","AZL-43969","AZL-44517","AZL-44754","AZL-44811","AZL-45174","AZL-45198","CLSA-2024-1716485905","EUVD-2023-59184","GHSA-vww9-j87r-4cqh"],"status":"published","title":"Memory corruption issues is Cloudflare zlib implementation","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.","severity":{"version":"3.1","score":4,"vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00235,"percentile":0.14582,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-122","CWE-126","CWE-20","CWE-787"],"published":"2024-01-04T11:11:07Z","modified":"2026-11-05T05:36:30Z","fixes":[{"ecosystem":"Azure Linux:3","package":"fltk","fixed_in":["1.3.8-1"],"sources":["osv"]},{"ecosystem":"Azure Linux:3","package":"teckit","fixed_in":["2.5.12-4"],"sources":["osv"]},{"ecosystem":"TuxCare:Ubuntu:18.04","package":"lib32z1","fixed_in":["1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:Ubuntu:18.04","package":"lib32z1-dev","fixed_in":["1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:Ubuntu:18.04","package":"libx32z1","fixed_in":["1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:Ubuntu:18.04","package":"libx32z1-dev","fixed_in":["1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:Ubuntu:18.04","package":"zlib1g","fixed_in":["1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:Ubuntu:18.04","package":"zlib1g-dev","fixed_in":["1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Azure Linux:2","package":"openjpeg2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.3.1-12"}]}]},{"source":"osv","ecosystem":"Azure Linux:2","package":"teckit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.5.9-4"}]}]},{"source":"osv","ecosystem":"Azure Linux:2","package":"clucene","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.3.3.4-38"}]}]},{"source":"osv","ecosystem":"Azure Linux:2","package":"fltk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"1.3.5-4"}]}]},{"source":"osv","ecosystem":"Azure Linux:2","package":"ogdi","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"4.1.0-9"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"openjpeg2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.3.1-12"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"fltk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.3.8-1"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"clucene","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.3.3.4-40"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"ogdi","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"4.1.1-3"}]}]},{"source":"osv","ecosystem":"Azure Linux:3","package":"teckit","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.12-4"}]}]},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"lib32z1","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"lib32z1-dev","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"libx32z1","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"libx32z1-dev","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"zlib1g","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"zlib1g-dev","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1:1.2.11.dfsg-0ubuntu2.2+tuxcare.els2"}]}]}],"products":[{"vendor":"cloudflare","product":"zlib"},{"vendor":"ruby","product":"zlib"}],"references":[{"url":"https://github.com/cloudflare/zlib","tags":["product","x_transferred","Product","package"]},{"url":"https://github.com/cloudflare/zlib/security/advisories/GHSA-vww9-j87r-4cqh","tags":["vendor-advisory","x_transferred","Patch","Third Party Advisory","advisory"]},{"url":"https://security.alpinelinux.org/vuln/CVE-2023-6992","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-6992","tags":["web","advisory"]},{"url":"https://errata.cloudlinux.com/ubuntu18-els/CLSA-2024-1716485905.html","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/6xxx/CVE-2023-6992.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2023-6992","title":"Memory corruption issues is Cloudflare zlib implementation","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T11:11:07.558Z","modified":"2024-09-06T18:16:58.376Z","cvss":[{"version":"3.1","score":4,"vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-20","CWE-122","CWE-126"],"updated_at":"2026-11-02T14:35:25.469654Z"}],"euvd":[{"id":"EUVD-2023-59184","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T11:11:07Z","modified":"2024-09-06T18:16:58Z","cvss":[{"version":"3.1","score":4,"vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium"}],"updated_at":"2026-11-03T00:56:01.652315Z"}],"nvd":[{"id":"CVE-2023-6992","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23.69Z","modified":"2026-06-17T06:51:49.91Z","cvss":[{"version":"3.1","score":4,"vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"}],"cwes":["CWE-20","CWE-122","CWE-126","CWE-787"],"updated_at":"2026-11-02T14:08:59.830468Z"}],"osv":[{"id":"ALPINE-CVE-2023-6992","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"withdrawn","published":"2024-01-04T12:15:23.69Z","modified":"2026-07-14T08:03:31.80019586Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:27:49.709457Z"},{"id":"AZL-43663","title":"CVE-2023-6992 affecting package openjpeg2 2.3.1-12","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-04-21T04:31:05.707904Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:28:05.284713Z"},{"id":"AZL-43807","title":"CVE-2023-6992 affecting package teckit 2.5.9-4","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-04-21T04:31:10.083431Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:28:05.284713Z"},{"id":"AZL-43870","title":"CVE-2023-6992 affecting package clucene 2.3.3.4-38","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-04-21T04:31:11.649945Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:28:05.284713Z"},{"id":"AZL-43957","title":"CVE-2023-6992 affecting package fltk 1.3.5-4","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-04-21T04:31:13.752607Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:28:05.284713Z"},{"id":"AZL-43969","title":"CVE-2023-6992 affecting package ogdi 4.1.0-9","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-04-21T04:31:13.620303Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:28:05.284713Z"},{"id":"AZL-44517","title":"CVE-2023-6992 affecting package openjpeg2 2.3.1-12","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-11-05T05:36:30Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-05T16:41:20.107976Z"},{"id":"AZL-44754","title":"CVE-2023-6992 affecting package fltk for versions less than 1.3.8-1","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-04-21T04:50:01.522154Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:28:05.694722Z"},{"id":"AZL-44811","title":"CVE-2023-6992 affecting package clucene 2.3.3.4-40","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-11-05T05:36:30Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-05T16:41:20.321068Z"},{"id":"AZL-45174","title":"CVE-2023-6992 affecting package ogdi 4.1.1-3","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-11-05T05:36:30Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-05T16:41:20.321068Z"},{"id":"AZL-45198","title":"CVE-2023-6992 affecting package teckit for versions less than 2.5.12-4","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T12:15:23Z","modified":"2026-04-21T04:55:16.204972Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:28:05.694722Z"},{"id":"CVE-2023-6992","title":"Memory corruption issues is Cloudflare zlib implementation","description":"Cloudflare version of zlib library was found to be vulnerable to memory corruption issues affecting the deflation algorithm implementation (deflate.c). The issues resulted from improper input validation and heap-based buffer overflow.\nA local attacker could exploit the problem during compression using a crafted malicious file potentially leading to denial of service of the software.\nPatches: The issue has been patched in commit  8352d10 https://github.com/cloudflare/zlib/commit/8352d108c05db1bdc5ac3bdf834dad641694c13c . The upstream repository is not affected.\n","status":"published","published":"2024-01-04T11:11:07.558Z","modified":"2026-10-28T02:31:08.913564344Z","cvss":[{"version":"3.1","score":4,"vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L","level":"medium"}],"cwes":["CWE-122","CWE-126","CWE-20"],"updated_at":"2026-11-02T15:44:37.180532Z"},{"id":"CLSA-2024-1716485905","title":"Fix CVE(s): CVE-2023-6992","description":"   * SECURITY UPDATE: heap-based buffer overflow\n     - debian/patches/CVE-2023-6992.patch: in deflace.c fix\n       incorrectly calculated min size of block.\n     - CVE-2023-6992","status":"published","published":"2024-05-23T17:38:28Z","modified":"2026-06-04T10:03:23.383068Z","updated_at":"2026-11-02T15:43:40.88185Z"}]}}