{"apiVersion":"1.0","identifier":"CVE-2026-50538","description":"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 is 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.","publishedAt":"2026-08-21T21:16:59","lastModifiedAt":"2026-08-24T20:16:44","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-50538","cvssScore":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","epssProbability":0.00321,"riskScore":0.91,"affectedProduct":"LibVNCClient","affectedVersions":">=0.9.12,<=0.9.15","vulnerabilityType":"Library","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-50538","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-50538","en":"https://www.redsauce.net/en/cves/CVE-2026-50538","fr":"https://www.redsauce.net/fr/cves/CVE-2026-50538","pt":"https://www.redsauce.net/pt/cves/CVE-2026-50538","de":"https://www.redsauce.net/de/cves/CVE-2026-50538","sk":"https://www.redsauce.net/sk/cves/CVE-2026-50538","el":"https://www.redsauce.net/el/cves/CVE-2026-50538"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-50538"}}