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CVE-2026-116591VulnerabilityPublished Updated

Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

Affects Red Hat compressSource GCVE Database

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Authoritative record:CVE-2026-116591· High 8.7

Not known to be exploited · CVSS 8.7 High : upgrade Red Hat compress to 1.20.2 soon.

Data as of 4 Nov 2026, 06:35 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 4.08.7
Patch
Available – fixed in 1.20.2
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.

What to do

Upgrade klauspost/compress to 1.20.2.

Affected software

ProductAffectedFixed in
GitHubklauspost/compresspkg:github/klauspost/compressOther threatsAffected
  • <1.20.2
Fixed in
  • 1.20.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Apply the official Red Hat update that includes the fixed klauspost/compress library version (1.20.2 or later) as provided in the Red Hat Hardened Images RPMs update. If you cannot patch yet, reject or filter untrusted Zstandard-compressed payloads at ingress proxies or restrict decompression endpoints to authenticated and trusted clients. No direct configuration-level workaround exists within the library itself. These mitigations reduce the risk but do not fix the underlying integer handling flaw.

Description

A vulnerability (CVE-2026-116591) exists in the klauspost compress library's Zstandard (zstd) decompression implementation used in Red Hat Hardened Images RPMs. An integer handling flaw in the decompression logic can be exploited by a remote attacker supplying a specially crafted compressed stream, causing an out-of-bounds read and an unhandled panic that crashes the application, resulting in a denial of service (DoS). The issue affects applications decompressing untrusted inputs using this library. No direct configuration workaround exists within the library itself. Mitigations include rejecting or filtering untrusted zstd-compressed payloads at ingress or restricting decompression to trusted clients. A fixed version is available in klauspost/compress 1.20.2 and corresponding Red Hat builds.

References

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