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 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.
- CVSS 3.1
- 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS
- 0.5% chance of exploitation in the next 30 days; higher than 42% of CVEs (scores of 2026-10-25)
- CWEs
- CWE-190, CWE-787
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-259r-337f-4rfw | Go | github.com/klauspost/compress | <1.18.7 | 1.18.7 |
| GO-2026-5841 | Go | github.com/klauspost/compress | >=1.16.0 <1.18.7 | 1.18.7 |