HIGH 7.5 NVD
CVE-2026-63209
compress provides various compression algorithms. Prior to version 1.18.7, a signed integer overflow vulnerability in s2.NewDict() allows an attacker to bypass
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.
References
- https://github.com/klauspost/compress/commit/539243b8823ee8f03e49969823d57c348c917536
- https://github.com/klauspost/compress/releases/tag/v1.18.7
- https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw
- https://github.com/klauspost/compress/security/advisories/GHSA-259r-337f-4rfw
This high severity vulnerability with a CVSS score of 7.5 was published on 2026-09-29 via NVD.
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