How severe is CVE-2026-42580?

CVE-2026-42580 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.

Is CVE-2026-42580 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42580?

CVE-2026-42580 affects Netty. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42580?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-42580 have an EU (EUVD) identifier?

Yes. CVE-2026-42580 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30123.

When was CVE-2026-42580 published?

CVE-2026-42580 was published on 2026-05-13 and last updated on 2026-06-17.

CVE-2026-42580

CVE-2026-42580 is a medium-severity vulnerability in Netty with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30123
Weakness: CWE-190
Affected product: Netty
Published: 2026-05-13
Last modified: 2026-06-17

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's chunk size parser silently overflows int, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Frequently asked questions

What is CVE-2026-42580?: Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's chunk size parser silently overflows int, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
How severe is CVE-2026-42580?: CVE-2026-42580 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.
Is CVE-2026-42580 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42580?: CVE-2026-42580 affects Netty. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42580?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42580 have an EU (EUVD) identifier?: Yes. CVE-2026-42580 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30123.
When was CVE-2026-42580 published?: CVE-2026-42580 was published on 2026-05-13 and last updated on 2026-06-17.

References

https://github.com/netty/netty/security/advisories/GHSA-m4cv-j2px-7723

Affected products (1)

cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

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