How severe is GHSA-vvp9-7p8x-rfvv?

No CVSS score has been assigned to GHSA-vvp9-7p8x-rfvv yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-vvp9-7p8x-rfvv?

GHSA-vvp9-7p8x-rfvv affects the following packages: lz4_flex (crates.io), lz4_flex (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-vvp9-7p8x-rfvv?

Update lz4_flex to 0.11.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vvp9-7p8x-rfvv is resolved across your whole dependency graph.

How do I detect GHSA-vvp9-7p8x-rfvv in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for lz4_flex. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-vvp9-7p8x-rfvv if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-vvp9-7p8x-rfvv?

O3 pinpoints whether GHSA-vvp9-7p8x-rfvv is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-vvp9-7p8x-rfvv actively exploited in the wild?

No public exploit code has been indexed for GHSA-vvp9-7p8x-rfvv yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-vvp9-7p8x-rfvv?

GHSA-vvp9-7p8x-rfvv has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 35th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-vvp9-7p8x-rfvv?

GHSA-vvp9-7p8x-rfvv is classified as CWE-201 (CWE-201), CWE-823 (CWE-823). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-vvp9-7p8x-rfvv published, and has it been updated?

GHSA-vvp9-7p8x-rfvv was published on March 16, 2026 and was last updated on March 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀 crates.io

GHSA-vvp9-7p8x-rfvv

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

Also known asCVE-2026-32829RUSTSEC-2026-0041

Published

Mar 16, 2026

Updated

Mar 20, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk35th percentile+0.43%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

2 pkgs affected

🦀lz4_flex🦀lz4_flex

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Decompressing invalid LZ4 data can leak data from uninitialized memory, or can leak content from previous decompression operations when reusing an output buffer.

Details

The LZ4 block format defines a "match copy operation" which duplicates previously written data or data from the user-supplied dict. The position of that data is defined by an offset. The data is copied within the output buffer from the offset to the current output position. However, lz4_flex did not properly detect invalid and out-of-bounds offset values properly, causing it to copy uninitialized data from the output buffer.

Only the block based API functions are affected: lz4_flex::block::{decompress_into, decompress_into_with_dict}

When safe-decode is disabled additionally these functions are affected lz4_flex::block::{decompress, decompress_with_dict, decompress_size_prepended, decompress_size_prepended_with_dict}

All frame APIs are not affected.

There are two affected use cases:

decompressing LZ4 data with the unsafe implementation (safe-decode feature flag disabled, which is enabled by default): can leak content of uninitialized memory as decompressed result
decompressing LZ4 data into a reused, user-supplied output buffer (affects the safe-decode feature as well): can leak the previous contents of the output buffer as decompressed result

Impact

Leakage of data from uninitialized memory or content from previous decompression operations, possibly revealing sensitive information and secrets.

Mitigation

lz4_flex 0.12.1 and 0.11.6 fixes this issue without requiring changes in user code.

If you cannot upgrade, you can mitigate this vulnerability by zeroing the output buffer before calling block::decompress_into or block::decompress_into_with_dict (only block based API is affected, frame API is not affected). Additionally the the safe-decode feature flag should be enabled.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`lz4_flex`	all versions	0.11.6
🦀crates.io	`lz4_flex`	≥ 0.12.0&&< 0.12.1	0.12.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for lz4_flex. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update lz4_flex to 0.11.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vvp9-7p8x-rfvv is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-vvp9-7p8x-rfvv is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-vvp9-7p8x-rfvv. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary Decompressing invalid LZ4 data can leak data from uninitialized memory, or can leak content from previous decompression operations when reusing an output buffer. ### Details The LZ4 block format defines a "match copy operation" which duplicates previously written data or data from the user-supplied dict. The position of that data is defined by an _offset_. The data is copied within the output buffer from the _offset_ to the current output position. However, lz4_flex did not properly detect invalid and out-of-bounds _offset_ values properly, causing it to copy uninitialized data fr

O3 Security · Impact-Aware SCA

Is GHSA-vvp9-7p8x-rfvv in your dependencies?

O3 detects GHSA-vvp9-7p8x-rfvv across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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