{"id":"CVE-2026-63381","summary":"Libevent: Dangling Pointer in `evbuffer_add_buffer_reference`","details":"Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains frees the initial empty chain without resetting outbuf-\u003efirst, outbuf-\u003elast, or outbuf-\u003elast_with_datap, and APPEND_CHAIN_MULTICAST subsequently dereferences the dangling chain pointer. A caller that can drive this buffer state can cause memory corruption or a process crash. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.","aliases":["GHSA-c2pj-cg4r-88c8"],"modified":"2026-09-11T08:36:41.501710Z","published":"2026-08-20T17:50:09.322Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-908"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63381.json"},"references":[{"type":"WEB","url":"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable"},{"type":"WEB","url":"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63381.json"},{"type":"ADVISORY","url":"https://github.com/libevent/libevent/security/advisories/GHSA-c2pj-cg4r-88c8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63381"},{"type":"FIX","url":"https://github.com/libevent/libevent/commit/5cb95ba2f804f8aff46f88d58391c71e1251cd1c"},{"type":"FIX","url":"https://github.com/libevent/libevent/commit/9db091b04f569be3a700fa9860ef02f90b830af9"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/libevent/libevent","events":[{"introduced":"0"},{"fixed":"df3ecad3a040fd6d4fad4287defe113395de6fd7"},{"fixed":"79ddfb460847999b807cba76d04e73891f29c6ee"},{"fixed":"5cb95ba2f804f8aff46f88d58391c71e1251cd1c"},{"fixed":"9db091b04f569be3a700fa9860ef02f90b830af9"}],"database_specific":{"extracted_events":[{"introduced":"2.2.0-alpha"},{"fixed":"2.2.2-alpha"},{"introduced":"0"},{"fixed":"2.1.13"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["release-2.1.12-stable","release-2.2.1-alpha","release-2.1.11-stable","release-2.1.10-stable","release-2.1.9-beta","release-2.1.8-stable","release-2.1.7-rc","release-2.1.6-beta","release-2.1.5-beta","release-2.1.4-alpha","release-2.1.3-alpha","release-2.1.2-alpha","release-2.1.1-alpha","release-2.0.10-stable","release-2.0.9-rc","release-2.0.8-rc","release-2.0.7-rc","release-2.0.6-rc","release-2.0.5-beta","release-2.0.4-alpha","release-2.0.3-alpha","release-2.0.1-alpha","release-1.1b"],"database_specific":{"vanir_signatures":[{"deprecated":false,"digest":{"function_hash":"159443554126248192493229143747497657830","length":554},"id":"CVE-2026-63381-09212634","signature_type":"Function","signature_version":"v1","source":"https://github.com/libevent/libevent/commit/df3ecad3a040fd6d4fad4287defe113395de6fd7","target":{"file":"test/regress_http.c","function":"http_check_transfer_encoding_test"}},{"id":"CVE-2026-63381-0ba2dac6","signature_type":"Line","signature_version":"v1","source":"https://github.com/libevent/libevent/commit/9db091b04f569be3a700fa9860ef02f90b830af9","target":{"file":"test/regress_buffer.c"},"deprecated":false,"digest":{"line_hashes":["105678715192188160709520855612608486706","151283490904270762572312309386640940040","83461397285652447208958418655755277743","142837236412004261651148993320484336258","15987118943341410568314047996597972163","24377155224956095092769298328840568428","331749468313827334154743087866987491260"],"threshold":0.9}},{"signature_version":"v1","source":"https://github.com/libevent/libevent/commit/5cb95ba2f804f8aff46f88d58391c71e1251cd1c","target":{"file":"buffer.c"},"deprecated":false,"digest":{"line_hashes":["9615268734269462808469541219936445000","82724829605032451376073306411905357248","288037613782262970305669138843883230920","75154680587046303569609440082479999097"],"threshold":0.9},"id":"CVE-2026-63381-16a20d46","signature_type":"Line"},{"id":"CVE-2026-63381-1f37dda6","signature_type":"Line","signature_version":"v1","source":"https://github.com/libevent/libevent/commit/5cb95ba2f804f8aff46f88d58391c71e1251cd1c","target":{"file":"test/regress_buffer.c"},"deprecated":false,"digest":{"line_hashes":["105678715192188160709520855612608486706","151283490904270762572312309386640940040","83461397285652447208958418655755277743","87720941875676372913401481888278485640","239941351800049281984595058068342428110","24377155224956095092769298328840568428","331749468313827334154743087866987491260"],"threshold":0.9}},{"id":"CVE-2026-63381-340af901","signature_type":"Line","signature_version":"v1","source":"https://github.com/libevent/libevent/commit/9db091b04f569be3a700fa9860ef02f90b830af9","target":{"file":"buffer.c"},"deprecated":false,"digest":{"threshold":0.9,"line_hashes":["9615268734269462808469541219936445000","82724829605032451376073306411905357248","288037613782262970305669138843883230920","75154680587046303569609440082479999097"]}},{"source":"https://github.com/libevent/libevent/commit/9db091b04f569be3a700fa9860ef02f90b830af9","target":{"file":"buffer.c","function":"evbuffer_add_buffer_reference"},"deprecated":false,"digest":{"function_hash":"125746571338556120751565663598148478168","length":650},"id":"CVE-2026-63381-7824d339","signature_type":"Function","signature_version":"v1"},{"deprecated":false,"digest":{"line_hashes":["270762094980121927552802584929566056086","37564212311334647331345684303177453724","168570413533780985513641597969239978857"],"threshold":0.9},"id":"CVE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