How severe is CVE-2026-42579?

CVE-2026-42579 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-42579 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-42579?

CVE-2026-42579 affects Netty. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-42579?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-42579 have an EU (EUVD) identifier?

Yes. CVE-2026-42579 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30122.

When was CVE-2026-42579 published?

CVE-2026-42579 was published on 2026-05-13 and last updated on 2026-06-30.

CVE-2026-42579

CVE-2026-42579 is a high-severity vulnerability in Netty with a CVSS 3.x base score of 7.5. 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-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30122
Weakness: CWE-20
Affected product: Netty
Published: 2026-05-13
Last modified: 2026-06-30

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirectional attack surface: malicious DNS responses can exploit the decoder, and user-influenced hostnames can exploit the encoder. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

Frequently asked questions

What is CVE-2026-42579?: Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirectional attack surface: malicious DNS responses can exploit the decoder, and user-influenced hostnames can exploit the encoder. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
How severe is CVE-2026-42579?: CVE-2026-42579 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-42579 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42579?: CVE-2026-42579 affects Netty. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42579?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42579 have an EU (EUVD) identifier?: Yes. CVE-2026-42579 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30122.
When was CVE-2026-42579 published?: CVE-2026-42579 was published on 2026-05-13 and last updated on 2026-06-30.

References

Affected products (1)

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

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