{"id":"CVE-2026-102559","title":"Libsoup: libsoup: heap buffer overflow during websocket client-frame masking","summary":"A flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, c…","severity":"high","cvss":8.6,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","cvssSource":"cna","cwe":["CWE-125"],"vendor":"Red Hat","product":"libsoup3","affected":["libsoup3 (all versions)","libsoup","libsoup (all versions)","libsoup (all versions)","libsoup (all versions)"],"published":"2026-09-29","updated":"2026-09-29","sourceUpdated":"2026-09-29T17:15:34.470Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-102559","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-102559"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2543285","label":"RHBZ#2543285"}],"tags":["cve.org"],"ingestedAt":"2026-09-29T17:41:02.260Z","slug":"CVE-2026-102559","body":"## Overview\n\nA flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, causing a heap buffer overflow.\n\n## Affected\n\n- `libsoup3 (all versions)`\n- `libsoup`\n- `libsoup (all versions)`\n- `libsoup (all versions)`\n- `libsoup (all versions)`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n### Workarounds\n\nTo mitigate this enforce application-level limits on outgoing WebSocket message sizes. Do not send untrusted bulk data as a single WebSocket message.","depth":"twilight","depthScore":47,"depthScoreParts":{"impact":47.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}