CVE-2026-32829

Summary

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.

Affected Software

VendorProductVersion RangeStatus
PSeitzlz4_flex< 0.11.6affected
PSeitzlz4_flex>= 0.12.0, < 0.12.1affected

Weaknesses

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

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

lz4_flex: lz4_flex’s decompression can leak information from uninitialized memory or reused output buffer

Additional References

References