How severe is CVE-2026-44249?

CVE-2026-44249 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-44249 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-44249?

CVE-2026-44249 affects Netty. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-44249?

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-2026-44249 have an EU (EUVD) identifier?

Yes. CVE-2026-44249 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36327.

When was CVE-2026-44249 published?

CVE-2026-44249 was published on 2026-06-11 and last updated on 2026-09-18.

CVE-2026-44249

CVE-2026-44249 is a high-severity vulnerability in Netty with a CVSS 3.x base score of 8.1. 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-284.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-36327
Weakness: CWE-284
Affected product: Netty
Published: 2026-06-11
Last modified: 2026-09-18

Description

Netty is a network application framework for development of protocol servers and clients. In netty-handler prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Frequently asked questions

What is CVE-2026-44249?: Netty is a network application framework for development of protocol servers and clients. In netty-handler prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
How severe is CVE-2026-44249?: CVE-2026-44249 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-44249 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-44249?: CVE-2026-44249 affects Netty. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-44249?: 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-2026-44249 have an EU (EUVD) identifier?: Yes. CVE-2026-44249 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36327.
When was CVE-2026-44249 published?: CVE-2026-44249 was published on 2026-06-11 and last updated on 2026-09-18.

References

Affected products (1)

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

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