{"id":"CVE-2026-91948","state":"PUBLISHED","title":"FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL","description":"FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual channel handling when CHANNEL_OPTION_SHOW_PROTOCOL is enabled. Authenticated clients can queue oversized channel messages that cause buffer underflow and corrupt heap memory including live pointers, potentially enabling code execution.","publishedAt":"2026-09-15T15:18:06.465Z","updatedAt":"2026-09-17T11:59:33.144Z","severity":{"score":7.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","source":"VulnCheck"},"assigner":"VulnCheck","products":["FreeRDP FreeRDP"],"affected":[{"vendor":"FreeRDP","product":"FreeRDP","defaultStatus":"unaffected","versions":[{"version":"3.28.0","status":"affected","lessThan":"3.31.0","versionType":"semver"},{"version":"3.31.0","status":"unaffected","versionType":"semver"}]}],"references":["https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9jcm-x588-gh26","https://github.com/FreeRDP/FreeRDP/commit/40d9202cd95551600c07437ce6bd5ecd7d31e57b","https://www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-write-via-show-protocol"],"weaknesses":["CWE-191"],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/91xxx/CVE-2026-91948.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-91948","state":"PUBLISHED","datePublished":"2026-09-15T15:18:06.465Z","dateUpdated":"2026-09-17T11:59:33.144Z","assignerShortName":"VulnCheck","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateReserved":"2026-09-15T11:07:01.913Z"},"containers":{"cna":{"title":"FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL","descriptions":[{"lang":"en","value":"FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual channel handling when CHANNEL_OPTION_SHOW_PROTOCOL is enabled. Authenticated clients can queue oversized channel messages that cause buffer underflow and corrupt heap memory including live pointers, potentially enabling code execution."}],"affected":[{"vendor":"FreeRDP","product":"FreeRDP","defaultStatus":"unaffected","versions":[{"version":"3.28.0","status":"affected","lessThan":"3.31.0","versionType":"semver"},{"version":"3.31.0","status":"unaffected","versionType":"semver"}]}],"references":[{"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9jcm-x588-gh26","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-9jcm-x588-gh26)"},{"url":"https://github.com/FreeRDP/FreeRDP/commit/40d9202cd95551600c07437ce6bd5ecd7d31e57b","tags":["patch"],"name":"Patch Commit"},{"url":"https://www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-write-via-show-protocol","name":"VulnCheck Advisory: FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL","tags":["third-party-advisory"]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"PRESENT","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":7.7,"baseSeverity":"HIGH"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-191","lang":"en","description":"Integer Underflow (Wrap or Wraparound)","type":"CWE"}]}],"providerMetadata":{"shortName":"VulnCheck","orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","dateUpdated":"2026-09-15T15:18:06.465Z"},"datePublic":"2026-09-01T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*","versionStartIncluding":"3.28.0","versionEndExcluding":"3.31.0"}]}]}],"credits":[{"lang":"en","value":"sam4k","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-16T03:56:31.656578Z","id":"CVE-2026-91948","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-17T11:59:33.144Z"}}]}}}