Is CVE-2026-42583 in the CISA KEV catalog?

No. CVE-2026-42583 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-42583?

CVE-2026-42583 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2026-42583?

CVE-2026-42583 has an EPSS score of 0.43% (34th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-42583

HIGH

7.5

CVSS v3

NVD

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Lz4FrameDecoder allocates a ByteBuf of size decompressedLength (up to 32 MB per block) before LZ4 runs. A peer only needs a 21-byte header plus compressedLength payload bytes - 22 bytes if compressedLength == 1 - to force that allocation. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CWE-400Resource Exhaustion CWE-770

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.43%probability of exploitation in 30 days

34thpercentile

Low risk: more likely to be exploited than 34% of all known CVEs.

References

https://github.com/netty/netty/security/advisories/GHSA-mj4r-2hfc-f8p6

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-18.