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.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-vvp9-7p8x-rfvv lz4_flex's decompression can leak information from uninitialized memory or reused output buffer
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 20 Mar 2026 01:00:00 +0000

Type Values Removed Values Added
Description No description is available for this CVE. 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.
Title lz4_flex: lz4_flex's decompression can leak information from uninitialized memory or reused output buffer lz4_flex: Decompression can leak information from uninitialized memory or reused output buffer
Weaknesses CWE-201
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}


Thu, 19 Mar 2026 09:45:00 +0000

Type Values Removed Values Added
First Time appeared Pseitz
Pseitz lz4 Flex
Vendors & Products Pseitz
Pseitz lz4 Flex

Thu, 19 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
Description No description is available for this CVE.
Title lz4_flex: lz4_flex's decompression can leak information from uninitialized memory or reused output buffer
Weaknesses CWE-823
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

threat_severity

Important


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-20T00:49:12.893Z

Reserved: 2026-03-16T17:35:36.698Z

Link: CVE-2026-32829

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-20T01:15:56.277

Modified: 2026-03-20T01:15:56.277

Link: CVE-2026-32829

cve-icon Redhat

Severity : Important

Publid Date: 2026-03-16T20:48:08Z

Links: CVE-2026-32829 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-03-19T08:57:13Z

Weaknesses