{"id":"CVE-2026-63209","state":"PUBLISHED","title":"Integer Overflow or Wraparound and Out-of-bounds Write in compress","description":"compress provides various compression algorithms. Prior to version 1.18.7, a signed integer overflow vulnerability in s2.NewDict() allows an attacker to bypass repeat index validation by supplying a dictionary with a uvarint-encoded repeat value exceeding MaxInt64. When Dict.Encode() is subsequently called, the overflowed negative repeat value causes an out-of-bounds memory access via unsafe.Pointer arithmetic, crashing the process with SIGSEGV. This issue has been patched in version 1.18.7.","publishedAt":"2026-09-29T14:58:53.366Z","updatedAt":"2026-09-29T16:32:32.677Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["klauspost compress"],"affected":[{"vendor":"klauspost","product":"compress","versions":[{"version":"< 1.18.7","status":"affected"}]}],"references":["https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw","https://github.com/klauspost/compress/commit/539243b8823ee8f03e49969823d57c348c917536","https://github.com/klauspost/compress/releases/tag/v1.18.7"],"weaknesses":["CWE-190","CWE-787"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/63xxx/CVE-2026-63209.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-63209","state":"PUBLISHED","datePublished":"2026-09-29T14:58:53.366Z","dateUpdated":"2026-09-29T16:32:32.677Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-15T22:19:06.906Z"},"containers":{"cna":{"title":"Integer Overflow or Wraparound and Out-of-bounds Write in compress","descriptions":[{"lang":"en","value":"compress provides various compression algorithms. Prior to version 1.18.7, a signed integer overflow vulnerability in s2.NewDict() allows an attacker to bypass repeat index validation by supplying a dictionary with a uvarint-encoded repeat value exceeding MaxInt64. When Dict.Encode() is subsequently called, the overflowed negative repeat value causes an out-of-bounds memory access via unsafe.Pointer arithmetic, crashing the process with SIGSEGV. This issue has been patched in version 1.18.7."}],"affected":[{"vendor":"klauspost","product":"compress","versions":[{"version":"< 1.18.7","status":"affected"}]}],"references":[{"url":"https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw","name":"https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/klauspost/compress/commit/539243b8823ee8f03e49969823d57c348c917536","name":"https://github.com/klauspost/compress/commit/539243b8823ee8f03e49969823d57c348c917536","tags":["x_refsource_MISC"]},{"url":"https://github.com/klauspost/compress/releases/tag/v1.18.7","name":"https://github.com/klauspost/compress/releases/tag/v1.18.7","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-190","lang":"en","description":"CWE-190: Integer Overflow or Wraparound","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"CWE-787: Out-of-bounds Write","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-29T14:58:53.366Z"},"source":{"advisory":"GHSA-259r-337f-4rfw","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-29T16:31:39.668233Z","id":"CVE-2026-63209","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-29T16:32:32.677Z"}}]}}}