Home/CVE/lz4_flex is a pure Rust implementation of LZ4 compression/decompression. In versions 0.11.5 and below, and 0.12.0, deco
CVE

CVE-2026-32829

lz4_flex is a pure Rust implementation of LZ4 compression/decompression. In versions 0.11.5 and below, and 0.12.0, deco

lz4_flex is a pure Rust implementation of LZ4 compression/decompression. In versions 0.11.5 and below, and 0.12.0, decompressing invalid LZ4 data can leak sensitive information from uninitialized memory or from previous decompression operations. The library fails to properly validate offset values during LZ4 "match copy operations," allowing out-of-bounds reads from the output buffer.

The block-based API functions (decompress_into, decompress_into_with_dict, and others when safe-decode is disabled) are affected, while all frame APIs are unaffected. The impact is potential exposure of sensitive data and secrets through crafted or malformed LZ4 input. This issue has been fixed in versions 0.11.6 and 0.12.1.

HIGH · CVSS 7.5 EPSS 0.00015
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-201Insertion of Sensitive Information Into Sent Data
CWE-823Use of Out-of-range Pointer Offset
▤

Affected Products & Versions

2
pseitz lz4 flex< 0.11.6
pseitz lz4 flexall versions
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
crates.io lz4_flex HIGH fixed in 0.11.6
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD20 Mar 2026 · 01:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

4
rhsaRHSA-2026:19712Important
rhsaRHSA-2026:22862Moderate
rhsaRHSA-2026:16354Important
rhsaRHSA-2026:11800Important
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/PSeitz/lz4_flex/commit/055502ee5d297ecd6bf448ac91c055c7f6df9b6dPatch
https://github.com/PSeitz/lz4_flex/security/advisories/GHSA-vvp9-7p8x-rfvvMitigationVendor Advisory
https://rustsec.org/advisories/RUSTSEC-2026-0041.htmlThird Party Advisory
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