{"api_version":"1","generated_at":"2026-11-11T05:45:00+00:00","cve":"CVE-2026-104259","urls":{"html":"https://cve.report/CVE-2026-104259","api":"https://cve.report/api/cve/CVE-2026-104259.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-104259","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-104259"},"summary":{"title":"ModSecurity: removeComments Transformation Fails to Strip Adjacent Comments, Enabling WAF Rule Bypass","description":"ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 2.9.15 and 3.0.17, msre_fn_removeComments_execute in apache2/re_tfns.c and inplace() in src/actions/transformations/remove_comments.cc implement t:removeComments by copying the character immediately after a comment terminator without re-evaluating it. Adjacent comments can therefore leave a later comment in the transformed value, allowing inline-comment obfuscation to bypass rules that depend on comment stripping. When a comment terminator is the final content, the same copy reads one byte beyond the input buffer. This issue is fixed in versions 2.9.15 and 3.0.17.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-11-09 22:18:22","updated_at":"2026-11-10 19:17:41"},"problem_types":["CWE-670","CWE-670 CWE-670: Always-Incorrect Control Flow Implementation"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"5.4","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N","baseScore":5.4,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"5.4","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N","data":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.4,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.17","name":"https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.17","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v2.9.15","name":"https://github.com/owasp-modsecurity/ModSecurity/releases/tag/v2.9.15","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qrch-pjfr-9g47","name":"https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-qrch-pjfr-9g47","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/owasp-modsecurity/ModSecurity/commit/264f348ae1823cb71cead3650b74c165678a1d46","name":"https://github.com/owasp-modsecurity/ModSecurity/commit/264f348ae1823cb71cead3650b74c165678a1d46","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/owasp-modsecurity/ModSecurity/commit/49a65f471d3130b91f7fff9bfac9fe8dd9b97c44","name":"https://github.com/owasp-modsecurity/ModSecurity/commit/49a65f471d3130b91f7fff9bfac9fe8dd9b97c44","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-104259","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-104259","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"owasp-modsecurity","product":"ModSecurity","version":"affected < 2.9.15","platforms":[]},{"source":"CNA","vendor":"owasp-modsecurity","product":"ModSecurity","version":"affected >= 3.0.0, < 3.0.17","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"104259","cve":"CVE-2026-104259","epss":"0.002230000","percentile":"0.129620000","score_date":"2026-11-10","updated_at":"2026-11-11 00:08:19"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-104259","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-11-10T18:18:32.704323Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-11-10T19:07:18.936Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"product":"ModSecurity","vendor":"owasp-modsecurity","versions":[{"status":"affected","version":"< 2.9.15"},{"status":"affected","version":">= 3.0.0, < 3.0.17"}]}],"descriptions":[{"lang":"en","value":"ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Prior to 2.9.15 and 3.0.17, msre_fn_removeComments_execute in apache2/re_tfns.c and inplace() in src/actions/transformations/remove_comments.cc implement t:removeComments by copying the character immediately after a comment terminator without re-evaluating it. Adjacent comments can therefore leave a later comment in the transformed value, allowing inline-comment obfuscation to bypass rules that depend on comment stripping. When a comment terminator is the final content, the same copy reads one byte beyond the input buffer. 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Prior to 2.9.15 and 3.0.17, msre_fn_removeComments_execute in apache2/re_tfns.c and inplace() in src/actions/transformations/remove_comments.cc implement t:removeComments by copying the character immediately after a comment terminator without re-evaluating it. Adjacent comments can therefore leave a later comment in the transformed value, allowing inline-comment obfuscation to bypass rules that depend on comment stripping. When a comment terminator is the final content, the same copy reads one byte beyond the input buffer. This issue is fixed in versions 2.9.15 and 3.0.17.","Type":"Description","Title":"ModSecurity: removeComments Transformation Fails to Strip Adjace"}]}}}