{"id":"DEBIAN-CVE-2026-42859","details":"Neat VNC is a VNC server library. Prior to 0.9.6, a pre-authentication stack buffer overflow exists in neatvnc in the RSA-AES security type handler. An unauthenticated remote attacker who can reach the VNC listening socket can send a crafted security type 5 (RSA-AES) or security type 129 (RSA-AES-256) handshake with an oversized client RSA public key, causing rsa_aes_send_challenge in src/auth/rsa-aes.c to overflow a 1024-byte on-stack buffer when encrypting the server challenge. This results in at least a denial of service via server crash. This vulnerability is fixed in 0.9.6.","modified":"2026-09-14T17:03:35.996394562Z","published":"2026-05-11T18:16:36.400Z","upstream":["CVE-2026-42859"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-42859"}],"affected":[{"package":{"name":"neatvnc","ecosystem":"Debian:12","purl":"pkg:deb/debian/neatvnc?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.5.4+dfsg-1","0.5.4+dfsg-2~exp1","0.6.0+dfsg-1","0.6.0+dfsg-2","0.6.0+dfsg-3","0.6.0+dfsg-4","0.7.0+dfsg-1","0.7.0+dfsg-1~exp1","0.7.1+dfsg-1","0.7.1+dfsg-2","0.8.0+dfsg-1","0.8.0+dfsg-2","0.8.0+dfsg-3","0.9.1+dfsg-1","0.9.1+dfsg-1.1","1.0.0+dfsg-1~exp1","1.0.1+dfsg-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42859.json"}},{"package":{"name":"neatvnc","ecosystem":"Debian:13","purl":"pkg:deb/debian/neatvnc?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.1+dfsg-1","0.9.1+dfsg-1.1","1.0.0+dfsg-1~exp1","1.0.1+dfsg-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42859.json"}},{"package":{"name":"neatvnc","ecosystem":"Debian:14","purl":"pkg:deb/debian/neatvnc?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.9.1+dfsg-1.1"}]}],"versions":["0.9.1+dfsg-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-42859.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}