{"id":"CVE-2026-112021","revision":"9926d1ec4ed14f2faea77269a51ae94b","records":[{"revision":"9926d1ec4ed14f2faea77269a51ae94b","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-112021","aliases":[],"title":"snac2 before 2.93 Heap-Based Buffer Overflow via JSON Parser _xs_json_load_lexer()","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.","state":0,"publishedAt":"2026-10-18T11:38:40.652+00:00","modifiedAt":"2026-10-19T16:05:15.544+00:00","affected":[{"ecosystem":"Vendor product","name":"snac2","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"grunfink\",\n                    \"product\": \"snac2\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.93\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"custom\"\n                        }\n                    ],\n                    \"repo\": \"https://codeberg.org/grunfink/snac2\"\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","score":8.7,"severity":"HIGH"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://nullenvk.pl/posts/02-snac2-json","https://gist.github.com/nullenvk/2bf288e2d34cb3d4b7143e61dbf7d90b","https://codeberg.org/grunfink/snac2/src/tag/2.92/xs_json.h#L283-L285","https://codeberg.org/grunfink/snac2/commit/ec2c5c2046e0381bc942ec5d0d05ec861fe377e7","https://codeberg.org/grunfink/snac2/releases/tag/2.93","https://codeberg.org/grunfink/snac2","https://www.vulncheck.com/advisories/snac2-before-2.93-heap-based-buffer-overflow-via-json-parser-xs-json-load-lexer"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-112021","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-112021","identifiers":["CVE-2026-112021"]},"retained":false,"historicalAffected":[]}],"coverage":[]}