{"id":"CVE-2026-75834","state":"PUBLISHED","title":"Grav before 2.0.14 Stored XSS via Invalid UTF-8 Byte","description":"Grav before 2.0.14 contains a stored cross-site scripting vulnerability in the Security::detectXss() function (system/src/Grav/Common/Security.php). All XSS detection patterns use the PCRE /u (UTF-8) modifier, so a single invalid UTF-8 byte anywhere in page content causes preg_match() to return false for every pattern, silently bypassing the save-time XSS safety gate (Validation::checkSafety()). An authenticated attacker with page-edit permissions (without the security.xss_whitelist privilege) can store malicious JavaScript that executes in the browser of a visitor who views the affected page.","publishedAt":"2026-08-18T11:19:45.094Z","updatedAt":"2026-10-08T15:24:58.750Z","severity":{"score":5.1,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["getgrav grav"],"affected":[{"vendor":"getgrav","product":"grav","packageURL":"pkg:composer/getgrav/grav","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.0.14","versionType":"semver"},{"version":"2.0.14","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/getgrav/grav/security/advisories/GHSA-q2j8-x8hf-63ch","https://www.vulncheck.com/advisories/grav-before-stored-xss-via-invalid-utf-8-byte"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/75xxx/CVE-2026-75834.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-75834","state":"PUBLISHED","datePublished":"2026-08-18T11:19:45.094Z","dateUpdated":"2026-10-08T15:24:58.750Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-08-18T10:57:39.580Z"},"containers":{"cna":{"title":"Grav before 2.0.14 Stored XSS via Invalid UTF-8 Byte","descriptions":[{"lang":"en","value":"Grav before 2.0.14 contains a stored cross-site scripting vulnerability in the Security::detectXss() function (system/src/Grav/Common/Security.php). All XSS detection patterns use the PCRE /u (UTF-8) modifier, so a single invalid UTF-8 byte anywhere in page content causes preg_match() to return false for every pattern, silently bypassing the save-time XSS safety gate (Validation::checkSafety()). An authenticated attacker with page-edit permissions (without the security.xss_whitelist privilege) can store malicious JavaScript that executes in the browser of a visitor who views the affected page."}],"affected":[{"vendor":"getgrav","product":"grav","packageURL":"pkg:composer/getgrav/grav","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.0.14","versionType":"semver"},{"version":"2.0.14","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/getgrav/grav/security/advisories/GHSA-q2j8-x8hf-63ch","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-q2j8-x8hf-63ch)"},{"url":"https://www.vulncheck.com/advisories/grav-before-stored-xss-via-invalid-utf-8-byte","name":"VulnCheck Advisory: Grav before 2.0.14 Stored XSS via Invalid UTF-8 Byte","tags":["third-party-advisory"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":5.1,"baseSeverity":"MEDIUM","exploitMaturity":"NOT_DEFINED","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"LOW","subIntegrityImpact":"LOW","userInteraction":"PASSIVE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS"},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.4,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-10-08T15:24:58.750Z"},"datePublic":"2026-08-03T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:*","versionEndExcluding":"2.0.14"}]}]}],"credits":[{"lang":"en","value":"iaohkut-from-NightWolf-Team","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-18T12:51:15.491121Z","id":"CVE-2026-75834","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-18T13:36:10.448Z"}}]}}}