{"id":"CVE-2026-112021","published":"2026-10-18T12:17:15.200","lastModified":"2026-10-18T12:17:15.200","description":"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.","cvssScore":7.5,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwes":["CWE-122"],"vendors":[],"products":[],"references":[{"url":"https://codeberg.org/grunfink/snac2","tags":[]},{"url":"https://codeberg.org/grunfink/snac2/commit/ec2c5c2046e0381bc942ec5d0d05ec861fe377e7","tags":[]},{"url":"https://codeberg.org/grunfink/snac2/releases/tag/2.93","tags":[]},{"url":"https://codeberg.org/grunfink/snac2/src/tag/2.92/xs_json.h#L283-L285","tags":[]},{"url":"https://gist.github.com/nullenvk/2bf288e2d34cb3d4b7143e61dbf7d90b","tags":[]},{"url":"https://nullenvk.pl/posts/02-snac2-json","tags":[]},{"url":"https://www.vulncheck.com/advisories/snac2-before-2.93-heap-based-buffer-overflow-via-json-parser-xs-json-load-lexer","tags":[]}],"exploitRefs":[{"url":"https://gist.github.com/nullenvk/2bf288e2d34cb3d4b7143e61dbf7d90b","tags":[]}],"hasPoc":true,"ai":null}