{"id":"CVE-2026-112021","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-112021","summary":"snac2 before 2.93 contains a heap-based buffer overflow vulnerability in _xs_json_load_lexer() that allows unauthenticated remote attackers to corrupt heap memory by sending JSON strings…","details":"snac2 before 2.93 contains a heap-based buffer overflow vulnerability in _xs_json_load_lexer() that allows unauthenticated remote attackers to corrupt heap memory by sending JSON strings containing a \\u0000 escape. Attackers can send a single crafted application/activity+json POST to activitypub_post_handler(), which parses it before signature checks, overflowing heap allocations and crashing the server.","published":"2026-10-18T11:38:40.652Z","modified":"2026-10-18T11:38:40.652Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"WEB","url":"https://nullenvk.pl/posts/02-snac2-json"},{"type":"EXPLOIT","url":"https://gist.github.com/nullenvk/2bf288e2d34cb3d4b7143e61dbf7d90b"},{"type":"WEB","url":"https://codeberg.org/grunfink/snac2/src/tag/2.92/xs_json.h#L283-L285"},{"type":"FIX","url":"https://codeberg.org/grunfink/snac2/commit/ec2c5c2046e0381bc942ec5d0d05ec861fe377e7"},{"type":"WEB","url":"https://codeberg.org/grunfink/snac2/releases/tag/2.93"},{"type":"WEB","url":"https://codeberg.org/grunfink/snac2"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/snac2-before-2.93-heap-based-buffer-overflow-via-json-parser-xs-json-load-lexer"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-10-18T11:38:40.652Z"}}