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  4. CVE 2026 116591 compress zstd panic on two block frames
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Back to active CVEs
High · CVSS 8.7CVE-2026-116591

compress zstd: Panic on two-block framesCVE-2026-116591

Answer in brief

CVE-2026-116591 records a High severity (CVSS 8.7) vulnerability in compress zstd: Panic on two-block frames. The current sources do not mark it as known exploited. The current feed maps klauspost/compress (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 26, 2026Updated Oct 26, 2026Source checked Oct 26, 2026First seen by HOL Oct 26, 2026Material review Oct 26, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 8.7
Exploitation
Not marked as known exploited
Affected software
1 mapped package or product
Fix availability
Available

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps klauspost/compress (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
klauspost/compressgeneric<1.20.21.20.2

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for klauspost/compress.
  2. 2Review the reported fix. Update klauspost/compress to 1.20.2 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Oct 26, 2026

    Evidence: source:cvelist:source_dates:source-dates:record
  2. Source modified

    Oct 26, 2026

    Evidence: source:cvelist:source_dates:source-dates:record
  3. First seen by HOL

    Oct 26, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
Upstream source description

compress provides various compression algorithms. Prior to 1.20.2, the zstd DecodeAll and streaming decoder paths can panic when a crafted two-block frame reaches huff0.ReadTable with an FSE normalized count of 32768 that readNCount stores in int16 as -32768. The wrapped count allows buildDtable to retain stale fse.Scratch decode-table state from the prior block, and nextFast then derives an out-of-range state and indexes beyond the table instead of returning a decode error. Both blocks are required to preserve and then reuse the stale state, allowing untrusted zstd input to crash an application. This issue is fixed in version 1.20.2.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • FLTK through 1.4.5 Heap Buffer Overflow via Fl_BMP_Image Integer OverflowAlso CWE-190
  • flatcc through 0.6.4 Out-of-Bounds Read via verifier check_headerAlso CWE-190

Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
CWE-190
Source
CVE List V5
Source checked
Oct 26, 2026
References
3 linked sources
Open source record