Vulnerability · Published Oct 6, 2026 · Assigned by GitHub_M

CVE-2026-106453yawkat 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

Medium 5.3

In plain English

A medium-severity security flaw in lz4-java from yawkat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.4%top 68.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

yawkat LZ4 Java provides LZ4 compression for Java. Prior to 1.11.2, LZ4DecompressorWithLength uses getDecompressedLength to trust the four-byte decompressed-length header before validating the compressed input, allowing a five-byte attacker-supplied input whose header declares a large output size to request up to approximately 2 GiB and exhaust the JVM heap. Convenience overloads backed by LZ4FastDecompressor or LZ4SafeDecompressor allocate the untrusted size, while overloads that write to a caller-provided destination buffer are not affected because the caller controls the destination size. This issue is fixed in version 1.11.2.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	lz4-java	no fix listed	DEBIAN-CVE-2026-106453
Debian:13	lz4-java	no fix listed	DEBIAN-CVE-2026-106453
Debian:14	lz4-java	1.11.2+ds1-1	DEBIAN-CVE-2026-106453
Maven	at.yawk.lz4:lz4-java	1.11.2	GHSA-6cx8-rjf8-pr8g
Maven	org.lz4:lz4-java	no fix listed	GHSA-6cx8-rjf8-pr8g
Ubuntu:22.04:LTS	lz4-java	no fix listed	UBUNTU-CVE-2026-106453
Ubuntu:24.04:LTS	lz4-java	no fix listed	UBUNTU-CVE-2026-106453
Ubuntu:26.04:LTS	lz4-java	no fix listed	UBUNTU-CVE-2026-106453
Ubuntu:26.10	lz4-java	no fix listed	UBUNTU-CVE-2026-106453

Affected products (as reported)

Vendor	Product	Versions
yawkat	lz4-java	< 1.11.2

Weakness: CWE-789 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

https://github.com/yawkat/lz4-java/security/advisories/GHSA-6cx8-rjf8-pr8g x_refsource_CONFIRM
https://github.com/yawkat/lz4-java/commit/6492ce5aca6bd03ff9e08ee18a2beb94c431371a x_refsource_MISC
https://github.com/yawkat/lz4-java/releases/tag/v1.11.2 x_refsource_MISC