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CVE-2026-106452 medium CVSS 5.3

Vulnerability in at.yawk.lz4:lz4-java (CVE-2026-106452)

Summary

Vulnerability in at.yawk.lz4:lz4-java (CVE-2026-106452). Risk of unauthorized operations or information disclosure. Exploitable via LZ4BlockInputStream. Mitigation: upgrade to 1.11.2 or later.

Original description

The description as published by the source.

Summary

LZ4BlockInputStream grows its compressed-input buffer to the attacker-controlled compressedLen value from the legacy LZ4Block stream header before reading any payload bytes. A header-only input can therefore trigger a near-2 GiB allocation and exhaust the JVM heap.

Details

In net.jpountz.lz4.LZ4BlockInputStream, refill() validates that compressedLen is nonnegative but does not cap it before allocation:

case COMPRESSION_METHOD_LZ4:
  if (compressedBuffer.length < compressedLen) {
    compressedBuffer = new byte[Math.max(compressedLen, compressedBuffer.length * 3 / 2)];
  }
  readFully(compressedBuffer, compressedLen);

The paired LZ4BlockOutputStream never emits such a block. If compression is not smaller than the original block, it writes the block as RAW:

if (compressedLength >= o) {
  compressMethod = COMPRESSION_METHOD_RAW;
  compressedLength = o;
} else {
  compressMethod = COMPRESSION_METHOD_LZ4;
}

Existing readers generally accept noncanonical LZ4-method blocks where compressedLen >= originalLen, but no canonical writer found produces them.

Impact

Applications that pass attacker-controlled legacy LZ4Block streams to LZ4BlockInputStream can suffer heap exhaustion from a header-only input. The impact is availability-only and requires no valid compressed payload.

Patch

As of lz4-java 1.11.2, lz4-java rejects lz4 blocks where the compressed length is larger than uncompressed. Readers would general…

Source: NIST National Vulnerability Database NVD GitHub Advisory

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-2026-106452 has been found in at.yawk.lz4:lz4-java.
Attackers can target a specific entry point like LZ4BlockInputStream over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade at.yawk.lz4:lz4-java to 1.11.2 or later.
If unsure, ask your IT team or search "at.yawk.lz4:lz4-java CVE-2026-106452" on the vendor's site.

CVE-2026-106452 (at.yawk.lz4:lz4-java) — CWE-789 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: LZ4BlockInputStream / compressedLen / LZ4Block / net.jpountz.lz4.LZ4BlockInputStream
Patched: 1.11.2 — apply immediately
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-789) exists in at.yawk.lz4:lz4-java. Attackers reach the vulnerable code path via LZ4BlockInputStream without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of at.yawk.lz4:lz4-java. Attack surface: LZ4BlockInputStream / compressedLen / LZ4Block / net.jpountz.lz4.LZ4BlockInputStream.

🔥 Severity

Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.11.2.

🛡️ 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. Audit SBOM/dependencies to find affected services.

Response actions

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

  1. 1
    Identify exposure identify 
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで at.yawk.lz4:lz4-java を使っているサービスとバージョンを洗い出す。

  2. 2
    Apply patch patch 
    Upgrade at.yawk.lz4:lz4-java to 1.11.2

    ステージング環境で 1.11.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    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。

Affected packages

maven at.yawk.lz4:lz4-java
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.11.2"}]}]
maven org.lz4:lz4-java
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]

References

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