{"id":"CVE-2026-63209","title":"compress provides various compression algorithms","summary":"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 repe…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-190","CWE-787"],"vendor":"klauspost","product":"compress","affected":["compress < 1.18.7"],"published":"2026-09-29","updated":"2026-09-29","sourceUpdated":"2026-09-29T17:17:08.843","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-63209","references":[{"url":"https://github.com/klauspost/compress/commit/539243b8823ee8f03e49969823d57c348c917536","label":"security-advisories@github.com"},{"url":"https://github.com/klauspost/compress/releases/tag/v1.18.7","label":"security-advisories@github.com"},{"url":"https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw","label":"security-advisories@github.com"},{"url":"https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-29T16:31:39.668233Z"},"ingestedAt":"2026-09-29T16:39:33.260Z","slug":"CVE-2026-63209","body":"## Overview\n\ncompress 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}