Zstd Decoder Vulnerability in Compress Library by Klaus Post
CVE-2026-116591

8.7HIGH

Key Information:

Vendor

Klauspost

Status
Compress
Vendor
CVE Published:
26 October 2026

What is CVE-2026-116591?

The Compress library prior to version 1.20.2 contains a vulnerability within its Zstd decoding functionality. Maliciously crafted input data can induce a panic condition in applications utilizing the library. Specifically, when specific two-block frames trigger a sequence that leads to an out-of-bounds condition in the FSE normalized count management, it creates a situation where the state of the decoder may reference invalid memory locations. This potentially results in application crashes, compromising stability and security. This issue has been resolved in version 1.20.2, and it is recommended that users upgrade to this version to mitigate risks.

Affected Version(s)

compress < 1.20.2

References

https://github.com/klauspost/compress/security/advisories...
x_refsource_CONFIRM
https://github.com/klauspost/compress/commit/7f5d8528720c...
x_refsource_MISC
https://github.com/klauspost/compress/releases/tag/v1.20.2
x_refsource_MISC

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.