{"schemaVersion":3,"id":"CVE-2026-50538","aliases":["SUSE-SU-2026:23601-1","SUSE-SU-2026:3803-1","SUSE-SU-2026:4022-1","SUSE-SU-2026:4024-1","UBUNTU-CVE-2026-50538","DEBIAN-CVE-2026-50538","openSUSE-SU-2026:11601-1","openSUSE-SU-2026:21735-1"],"status":"published","duplicateOf":null,"title":null,"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\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.","dates":{"published":"2026-08-21T21:03:58.147Z","modified":"2026-08-24T19:39:57.811Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":8.8,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":8.8,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":8.8,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","exploitability":7.2,"impact":9.8,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":8.8,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","exploitability":7.2,"impact":9.8,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":8.8,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00404,"percentile":0.33204,"severity":"low","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":0.083,"baselineDate":"2026-09-20T00:00:00.000Z","baselineScore":0.00321},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00404,"percentile":0.33204}],"last30":[{"date":"2026-09-20T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00321,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00605,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00404,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00404,"percentile":0.33204}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-122","name":"Heap-based Buffer Overflow","description":"A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().","type":"weakness","status":"Draft","abstraction":"Variant","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/122.html"},{"id":"CWE-787","name":"Out-of-bounds Write","description":"The product writes data past the end, or before the beginning, of the intended buffer.","type":"weakness","status":"Draft","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/787.html"}],"affected":[{"vendor":"debian","product":"libvncserver","name":"libvncserver","label":"libvncserver","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/libvncserver","purlType":"deb","versions":[{"text":"< 0.9.14+dfsg-1+deb12u2","noFixRecorded":false,"fixedIn":null},{"text":"< 0.9.15+dfsg-1+deb13u2","noFixRecorded":false,"fixedIn":null},{"text":"< 0.9.15+dfsg-6","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.14+dfsg-1+deb12u2 | < 0.9.15+dfsg-1+deb13u2 | < 0.9.15+dfsg-6","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"italc","name":"italc","label":"italc","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/italc","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"libvncserver","name":"libvncserver","label":"libvncserver","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/libvncserver","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null},{"text":"< 0.9.13+dfsg-3ubuntu0.2","noFixRecorded":false,"fixedIn":null},{"text":"< 0.9.14+dfsg-1ubuntu0.2","noFixRecorded":false,"fixedIn":null},{"text":"< 0.9.15+dfsg-1ubuntu0.2","noFixRecorded":false,"fixedIn":null},{"text":"< 0.9.15+dfsg-3ubuntu0.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"All versions (No fix recorded) | < 0.9.13+dfsg-3ubuntu0.2 | < 0.9.14+dfsg-1ubuntu0.2 | < 0.9.15+dfsg-1ubuntu0.2 | < 0.9.15+dfsg-3ubuntu0.2","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"tightvnc","name":"tightvnc","label":"tightvnc","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/tightvnc","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"veyon","name":"veyon","label":"veyon","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/veyon","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"vino","name":"vino","label":"vino","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/vino","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"x11vnc","name":"x11vnc","label":"x11vnc","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/x11vnc","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"libvnc","product":"libvncserver","name":"libvncserver","label":"libvncserver","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 0.9.12, ≤ 0.9.15","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 0.9.12, ≤ 0.9.15","eol":null,"hubHref":"/vendor/libvnc/libvncserver"},{"vendor":"opensuse","product":"LibVNCServer&distro=openSUSE Leap 16.0","name":"LibVNCServer","label":"LibVNCServer&distro=openSUSE Leap 16.0","ecosystem":"openSUSE","cpePart":null,"purl":"pkg:rpm/opensuse/LibVNCServer&distro=openSUSE Leap 16.0","purlType":"rpm","versions":[{"text":"< 0.9.14-160000.6.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.14-160000.6.1","eol":null,"hubHref":null},{"vendor":"opensuse","product":"LibVNCServer&distro=openSUSE Tumbleweed","name":"LibVNCServer","label":"LibVNCServer&distro=openSUSE Tumbleweed","ecosystem":"openSUSE","cpePart":null,"purl":"pkg:rpm/opensuse/LibVNCServer&distro=openSUSE Tumbleweed","purlType":"rpm","versions":[{"text":"< 0.9.15-4.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.15-4.1","eol":null,"hubHref":null},{"vendor":"suse","product":"LibVNCServer&distro=SUSE Linux Enterprise Module for Package Hub 15 SP7","name":"LibVNCServer","label":"LibVNCServer&distro=SUSE Linux Enterprise Module for Package Hub 15 SP7","ecosystem":"SUSE Linux Enterprise","cpePart":null,"purl":"pkg:rpm/suse/LibVNCServer&distro=SUSE Linux Enterprise Module for Package Hub 15 SP7","purlType":"rpm","versions":[{"text":"< 0.9.10-150000.4.41.1","noFixRecorded":false,"fixedIn":null},{"text":"< 0.9.14-150600.3.12.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.10-150000.4.41.1 | < 0.9.14-150600.3.12.1","eol":null,"hubHref":null},{"vendor":"suse","product":"LibVNCServer&distro=SUSE Linux Enterprise Server 12 SP5-LTSS","name":"LibVNCServer","label":"LibVNCServer&distro=SUSE Linux Enterprise Server 12 SP5-LTSS","ecosystem":"SUSE Linux Enterprise","cpePart":null,"purl":"pkg:rpm/suse/LibVNCServer&distro=SUSE Linux Enterprise Server 12 SP5-LTSS","purlType":"rpm","versions":[{"text":"< 0.9.9-17.50.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.9-17.50.1","eol":null,"hubHref":null},{"vendor":"suse","product":"LibVNCServer&distro=SUSE Linux Enterprise Server 16.0","name":"LibVNCServer","label":"LibVNCServer&distro=SUSE Linux Enterprise Server 16.0","ecosystem":"SUSE Linux Enterprise","cpePart":null,"purl":"pkg:rpm/suse/LibVNCServer&distro=SUSE Linux Enterprise Server 16.0","purlType":"rpm","versions":[{"text":"< 0.9.14-160000.6.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.14-160000.6.1","eol":null,"hubHref":null},{"vendor":"suse","product":"LibVNCServer&distro=SUSE Linux Enterprise Server for SAP applications 16.0","name":"LibVNCServer","label":"LibVNCServer&distro=SUSE Linux Enterprise Server for SAP applications 16.0","ecosystem":"SUSE Linux Enterprise","cpePart":null,"purl":"pkg:rpm/suse/LibVNCServer&distro=SUSE Linux Enterprise Server for SAP applications 16.0","purlType":"rpm","versions":[{"text":"< 0.9.14-160000.6.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.14-160000.6.1","eol":null,"hubHref":null},{"vendor":"suse","product":"LibVNCServer&distro=SUSE Linux Enterprise Server LTSS Extended Security 12 SP5","name":"LibVNCServer","label":"LibVNCServer&distro=SUSE Linux Enterprise Server LTSS Extended Security 12 SP5","ecosystem":"SUSE Linux Enterprise","cpePart":null,"purl":"pkg:rpm/suse/LibVNCServer&distro=SUSE Linux Enterprise Server LTSS Extended Security 12 SP5","purlType":"rpm","versions":[{"text":"< 0.9.9-17.50.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.9-17.50.1","eol":null,"hubHref":null},{"vendor":"suse","product":"LibVNCServer&distro=SUSE Linux Enterprise Workstation Extension 15 SP7","name":"LibVNCServer","label":"LibVNCServer&distro=SUSE Linux Enterprise Workstation Extension 15 SP7","ecosystem":"SUSE Linux Enterprise","cpePart":null,"purl":"pkg:rpm/suse/LibVNCServer&distro=SUSE Linux Enterprise Workstation Extension 15 SP7","purlType":"rpm","versions":[{"text":"< 0.9.14-150600.3.12.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 0.9.14-150600.3.12.1","eol":null,"hubHref":null}],"affectedCount":16,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/LibVNC/libvncserver/security/advisories/GHSA-v9pm-47h4-jcq8","label":"github.com/LibVNC/libvncserver/security/advisories/GHSA-v9pm-47h4-jcq8","hostname":"github.com","tags":["X Refsource CONFIRM","REPORT"]},{"url":"https://github.com/LibVNC/libvncserver/commit/540332be3e0acc566fa64da6f1b4680c72c724dd","label":"github.com/LibVNC/libvncserver/commit/540332be3e0acc566fa64da6f1b4680c72c724dd","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-202623601-1/","label":"www.suse.com/support/update/announcement/2026/suse-su-202623601-1/","hostname":"www.suse.com","tags":["Advisory"]},{"url":"https://bugzilla.suse.com/1276218","label":"bugzilla.suse.com/1276218","hostname":"bugzilla.suse.com","tags":["REPORT"]},{"url":"https://www.suse.com/security/cve/CVE-2026-50538","label":"www.suse.com/security/cve/CVE-2026-50538","hostname":"www.suse.com","tags":["WEB"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-20263803-1/","label":"www.suse.com/support/update/announcement/2026/suse-su-20263803-1/","hostname":"www.suse.com","tags":["Advisory"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-20264022-1/","label":"www.suse.com/support/update/announcement/2026/suse-su-20264022-1/","hostname":"www.suse.com","tags":["Advisory"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-20264024-1/","label":"www.suse.com/support/update/announcement/2026/suse-su-20264024-1/","hostname":"www.suse.com","tags":["Advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-50538","label":"ubuntu.com/security/CVE-2026-50538","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-50538","label":"www.cve.org/CVERecord?id=CVE-2026-50538","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://ubuntu.com/security/notices/USN-8494-1","label":"ubuntu.com/security/notices/USN-8494-1","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-50538","label":"security-tracker.debian.org/tracker/CVE-2026-50538","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["MGASA-2026-0315"],"duplicates":[],"related":["USN-8494-1"]},"timeline":[{"kind":"published","date":"2026-08-21T21:03:58.147Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-08-24T19:39:57.811Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":35,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T14:29:33.792Z","stale":false,"partial":false}}