{"id":"CVE-2021-42785","aliases":["EUVD-2021-29741","GHSA-7q87-cj95-29mc","UBUNTU-CVE-2021-42785"],"status":"published","title":"Buffer Overflow in tvnviewer.exe via Crafted Packet in TightVNC Viewer 2.8.59","description":"Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server.","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-11","score":0.02342,"percentile":0.83852,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-120"],"published":"2021-11-23T21:37:07Z","modified":"2026-06-17T04:10:08Z","affected":[{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"tightvnc","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.10-0ubuntu2","1.3.10-0ubuntu3"]}],"products":[{"vendor":"glavsoft llc","product":"tightvnc viewer"},{"vendor":"tightvnc","product":"tightvnc"}],"references":[{"url":"https://www.tightvnc.com/whatsnew.php","tags":["x_refsource_MISC","x_transferred","Release Notes","Vendor Advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-42785"},{"url":"https://github.com/advisories/GHSA-7q87-cj95-29mc"},{"url":"https://ubuntu.com/security/CVE-2021-42785","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-42785","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-42785","title":"Buffer Overflow in tvnviewer.exe via Crafted Packet in TightVNC Viewer 2.8.59","description":"Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server.","status":"published","published":"2021-11-23T21:37:07Z","modified":"2024-08-04T03:38:50.226Z","cwes":["CWE-120"],"updated_at":"2026-11-02T14:32:58.739039Z"}],"euvd":[{"id":"EUVD-2021-29741","description":"Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server.","status":"published","published":"2021-11-23T21:37:07Z","modified":"2024-08-04T03:38:50Z","updated_at":"2026-11-03T03:24:15.299027Z"}],"ghsa":[{"id":"GHSA-7q87-cj95-29mc","title":"Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to...","description":"Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server.","status":"published","published":"2021-11-24T00:00:26Z","modified":"2023-02-01T05:06:36Z","cwes":["CWE-120"],"updated_at":"2026-11-02T14:50:22.895109Z"}],"nvd":[{"id":"CVE-2021-42785","description":"Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server.","status":"published","published":"2021-11-23T22:15:08.133Z","modified":"2026-06-17T04:10:08.66Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-120"],"updated_at":"2026-11-02T14:07:01.428028Z"}],"osv":[{"id":"UBUNTU-CVE-2021-42785","description":"Buffer Overflow vulnerability in tvnviewer.exe of TightVNC Viewer allows a remote attacker to execute arbitrary instructions via a crafted FramebufferUpdate packet from a VNC server.","status":"published","published":"2021-11-23T22:15:00Z","modified":"2025-10-24T04:50:36Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:54:29.220315Z"}]}}