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

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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.

Source published

6 Oct 2026 19:54:04 UTC

Source modified

7 Oct 2026 17:07:33 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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