{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63387","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-07-16T17:39:30.171Z","datePublished":"2026-08-20T17:53:41.863Z","dateUpdated":"2026-08-25T15:12:12.129Z"},"containers":{"cna":{"title":"Libevent: Off-by-one stack buffer overflow in dnsname_to_labels via crafted DNS server response","problemTypes":[{"descriptions":[{"cweId":"CWE-121","lang":"en","description":"CWE-121: Stack-based Buffer Overflow","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-193","lang":"en","description":"CWE-193: Off-by-one Error","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"CWE-787: Out-of-bounds Write","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7,"baseSeverity":"HIGH","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H","version":"3.1"}}],"references":[{"name":"https://github.com/libevent/libevent/security/advisories/GHSA-58rx-7448-jw47","tags":["x_refsource_CONFIRM"],"url":"https://github.com/libevent/libevent/security/advisories/GHSA-58rx-7448-jw47"},{"name":"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable","tags":["x_refsource_MISC"],"url":"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable"},{"name":"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha","tags":["x_refsource_MISC"],"url":"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"}],"affected":[{"vendor":"libevent","product":"libevent","versions":[{"version":">= 2.2.0-alpha, < 2.2.2-alpha","status":"affected"},{"version":"< 2.1.13","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-08-20T17:53:41.863Z"},"descriptions":[{"lang":"en","value":"Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an off-by-one stack buffer overflow in evdns.c when dnsname_to_labels formats a name-bearing DNS record at the end of the 64 KB stack buffer allocated by evdns_server_request_format_response. The final-label check permits j plus label_len plus one to equal buf_len, after which the terminating null byte is written to buf[buf_len]. A crafted DNS server response containing PTR, CNAME, MX, NS, or SOA data can trigger the one-byte out-of-bounds write and crash or corrupt the process. This issue is fixed in versions 2.1.13 and 2.2.2-alpha."}],"source":{"advisory":"GHSA-58rx-7448-jw47","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/libevent/libevent/security/advisories/GHSA-58rx-7448-jw47","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-25T15:11:49.042805Z","id":"CVE-2026-63387","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-25T15:12:12.129Z"}}]}}