Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
Affects Red Hat compressSource GCVE Database
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
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 4.0 | 8.7 |
|---|
- 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:NExploitation evidence
Disclosed: evidence found.
CVE published 26 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
GitHubklauspost/compresspkg:github/klauspost/compressOther threats | Affected
| Fixed in
|
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
- access.redhat.com/errata/RHSA-2026:92903 (opens in a new tab)
- images.redhat.com (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-116591 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_92903.json (opens in a new tab)