yawkat LZ4 Java: LZ4DecompressorWithLength allocates the unvalidated size from the 4-byte length header, so a 5-byte input triggers a 1 GiB allocation and OutOfMemoryError

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2026-106453: 0.37% estimated exploitation activity in the next 30 days; percentile 31.16 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary LZ4DecompressorWithLength.decompress(byte[], int) allocates whatever size the 4-byte length header declares, before it reads a single byte of compressed data. A 5-byte input whose header says 0x40000000 makes the JVM commit a gigabyte and can cause heap exhaustion. Details net.jpountz.lz4.LZ4DecompressorWithLength reads the header and passes it straight on: and net.jpountz.lz4.LZ4FastDecompressor allocates it: getDecompressedLength performs no validation: no comparison against src.length, no ceiling, no rejection of negatives. LZ4SafeDecompressor.decompress(byte[], int, int, int) has the same shape with maxDestLen. The sibling overload that callers pass their own buffer to, decompress(src, srcOff, dest, destOff, destLen), is fine, because there destLen is chosen by the caller rather than by the input. The bug is specific to the convenience overloads that take the size from the header, and that difference is the whole finding. Impact Any application that decompresses…

Published by the source

7 Oct 2026, 16:17 UTC

Last modified by the source

7 Oct 2026, 16:30 UTC

Source last checked

26 Oct 2026, 16:58 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-6cx8-rjf8-pr8g

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-6cx8-rjf8-pr8g

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# Patch Next advisory brief: CVE-2026-106453

Advisory: yawkat LZ4 Java: LZ4DecompressorWithLength allocates the unvalidated size from the 4-byte length header, so a 5-byte input triggers a 1 GiB allocation and OutOfMemoryError
IDs: CVE-2026-106453, GHSA-6cx8-rjf8-pr8g
Record: https://patchnext.com/advisories/cve-2026-106453 (revision 2, source checked 26 Oct 2026, 16:58 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: at.yawk.lz4:lz4-java 1.11.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven at.yawk.lz4:lz4-java: affected <= 1.11.1; fixed in 1.11.2
- Maven org.lz4:lz4-java: affected <= 1.8.1

## Suggested inspection (read-only)
- Maven at.yawk.lz4:lz4-java: check the installed version with your package manager.
- Maven org.lz4:lz4-java: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on at.yawk.lz4:lz4-java, org.lz4:lz4-java.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-6cx8-rjf8-pr8g (OSV record GHSA-6cx8-rjf8-pr8g lists affected ranges: Maven at.yawk.lz4:lz4-java >=0 =0 <=1.8.1)
- Verified: https://github.com/advisories/GHSA-6cx8-rjf8-pr8g (GitHub-reviewed advisory GHSA-6cx8-rjf8-pr8g lists affected ranges: Maven at.yawk.lz4:lz4-java >=0 =0 <=1.8.1)

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