How severe is CVE-2026-50009?

CVE-2026-50009 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability low.

Is CVE-2026-50009 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-50009?

CVE-2026-50009 affects Netty. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-50009?

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

Does CVE-2026-50009 have an EU (EUVD) identifier?

Yes. CVE-2026-50009 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36462.

When was CVE-2026-50009 published?

CVE-2026-50009 was published on 2026-06-12 and last updated on 2026-06-17.

CVE-2026-50009

CVE-2026-50009 is a medium-severity vulnerability in Netty with a CVSS 3.x base score of 4.8. 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-200.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
EPSS exploit prediction: 0% (10th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-36462
Weakness: CWE-200
Affected product: Netty
Published: 2026-06-12
Last modified: 2026-06-17

Description

Netty is a network application framework for development of protocol servers and clients. Prior to version 4.2.15.Final, Netty QUIC exposes the stateless reset token on the network path when using the default HMAC-based connection-ID and stateless-reset-token generators. The reset token for the server's current source connection ID can be derived from bytes that appear as the connection ID in QUIC headers after a source-CID rotation. An on-path attacker observing the headers can use the token to perform a Denial of Service by sending a spoofed Stateless Reset packet. Version 4.2.15.Final patches the issue.

Frequently asked questions

What is CVE-2026-50009?: Netty is a network application framework for development of protocol servers and clients. Prior to version 4.2.15.Final, Netty QUIC exposes the stateless reset token on the network path when using the default HMAC-based connection-ID and stateless-reset-token generators. The reset token for the server's current source connection ID can be derived from bytes that appear as the connection ID in QUIC headers after a source-CID rotation. An on-path attacker observing the headers can use the token to perform a Denial of Service by sending a spoofed Stateless Reset packet. Version 4.2.15.Final patches the issue.
How severe is CVE-2026-50009?: CVE-2026-50009 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability low.
Is CVE-2026-50009 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-50009?: CVE-2026-50009 affects Netty. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-50009?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-50009 have an EU (EUVD) identifier?: Yes. CVE-2026-50009 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36462.
When was CVE-2026-50009 published?: CVE-2026-50009 was published on 2026-06-12 and last updated on 2026-06-17.

References

Affected products (1)

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

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