{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-50538","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-06-04T20:37:18.653Z","datePublished":"2026-08-21T21:03:58.147Z","dateUpdated":"2026-08-24T19:39:57.811Z"},"containers":{"cna":{"title":"libvncclient Tight decoder has an attacker-controlled heap out-of-bounds write","problemTypes":[{"descriptions":[{"cweId":"CWE-122","lang":"en","description":"CWE-122: Heap-based Buffer Overflow","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"CWE-787: Out-of-bounds Write","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"name":"https://github.com/LibVNC/libvncserver/security/advisories/GHSA-v9pm-47h4-jcq8","tags":["x_refsource_CONFIRM"],"url":"https://github.com/LibVNC/libvncserver/security/advisories/GHSA-v9pm-47h4-jcq8"},{"name":"https://github.com/LibVNC/libvncserver/commit/540332be3e0acc566fa64da6f1b4680c72c724dd","tags":["x_refsource_MISC"],"url":"https://github.com/LibVNC/libvncserver/commit/540332be3e0acc566fa64da6f1b4680c72c724dd"}],"affected":[{"vendor":"LibVNC","product":"libvncserver","versions":[{"version":">= 0.9.12, <= 0.9.15","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-08-21T21:03:58.147Z"},"descriptions":[{"lang":"en","value":"LibVNCClient is a library for easy implementation of a VNC client. In versions 0.9.12 through 0.9.15, a malicious (or man-in-the-middle) VNC server can force a connecting `libvncclient` to write attacker-controlled data past the end of its framebuffer. This is an out-of-bounds heap write with attacker-controlled length, contents, and offset. It needs no authentication (the attacker\nis the server), works in a default build with default settings, and fires from a single `FramebufferUpdate` the moment the victim connects. It crashes any client unconditionally (denial of service); we also demonstrated it overwriting an application callback pointer and redirecting execution to attacker-chosen code (code execution) under the default configuration. Commit 540332be3e0acc566fa64da6f1b4680c72c724dd patches the issue."}],"source":{"advisory":"GHSA-v9pm-47h4-jcq8","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/LibVNC/libvncserver/security/advisories/GHSA-v9pm-47h4-jcq8","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-24T19:39:31.246844Z","id":"CVE-2026-50538","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-24T19:39:57.811Z"}}]}}