{"id":"DEBIAN-CVE-2026-44988","details":"LibVNCClient is a library for easy implementation of a VNC client. In 0.9.15 and earlier, LibVNCClient's Tight encoding decoder uses fixed-size 2048-pixel scratch buffers for the Gradient filter, but it does not reject Tight rectangles whose width is larger than 2048 pixels. A malicious VNC server can send a crafted FramebufferUpdate rectangle using Tight encoding with NoZlib | ExplicitFilter and the Gradient filter. When a LibVNCClient-based client connects, the client processes the server-controlled rectangle width and writes beyond fixed-size Gradient buffers. This vulnerability is fixed with commit 5b270544b85233668b98161323297d418a8f5fd1.","modified":"2026-09-01T16:06:44.976480072Z","published":"2026-05-27T15:16:29.830Z","upstream":["CVE-2026-44988"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-44988"}],"affected":[{"package":{"name":"libvncserver","ecosystem":"Debian:12","purl":"pkg:deb/debian/libvncserver?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.14+dfsg-1+deb12u2"}]}],"versions":["0.9.14+dfsg-1","0.9.14+dfsg-1+deb12u1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44988.json"}},{"package":{"name":"libvncserver","ecosystem":"Debian:13","purl":"pkg:deb/debian/libvncserver?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.15+dfsg-1+deb13u2"}]}],"versions":["0.9.15+dfsg-1","0.9.15+dfsg-1+deb13u1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44988.json"}},{"package":{"name":"libvncserver","ecosystem":"Debian:14","purl":"pkg:deb/debian/libvncserver?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.15+dfsg-5"}]}],"versions":["0.9.15+dfsg-1","0.9.15+dfsg-2","0.9.15+dfsg-3","0.9.15+dfsg-4"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44988.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}