Categories
CVE-2026-32829 high CVSS 7.5

Vulnerability in lz4_flex (CVE-2026-32829)

Summary

Vulnerability in lz4_flex (CVE-2026-32829). Confidential information can be exposed externally. Exploitable via decompress_into.

Original description

The description as published by the source.

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.

Source: NIST National Vulnerability Database NVD

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-32829 has been found in lz4_flex.
Attackers can target a specific entry point like decompress_into over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "lz4_flex CVE-2026-32829" on the vendor's site.

CVE-2026-32829 (lz4_flex) — CWE-201 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: decompress_into / decompress_into_with_dict
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-201) exists in lz4_flex. Attackers reach the vulnerable code path via decompress_into without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of lz4_flex. Attack surface: decompress_into / decompress_into_with_dict.

🔥 Severity

Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'lz4_flex' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify
    grep -r 'lz4_flex' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で lz4_flex を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Post-deployment verification verify
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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