How severe is CVE-2025-67735?

CVE-2025-67735 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 low, integrity low, and availability none.

Is CVE-2025-67735 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-67735?

CVE-2025-67735 affects Netty. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-67735?

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

Does CVE-2025-67735 have an EU (EUVD) identifier?

Yes. CVE-2025-67735 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-203450.

When was CVE-2025-67735 published?

CVE-2025-67735 was published on 2025-12-16 and last updated on 2026-06-17.

CVE-2025-67735

CVE-2025-67735 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-93.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (21st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-203450
Weakness: CWE-93
Affected product: Netty
Published: 2025-12-16
Last modified: 2026-06-17

Description

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.129.Final and 4.2.8.Final, the `io.netty.handler.codec.http.HttpRequestEncoder` has a CRLF injection with the request URI when constructing a request. This leads to request smuggling when `HttpRequestEncoder` is used without proper sanitization of the URI. Any application / framework using `HttpRequestEncoder` can be subject to be abused to perform request smuggling using CRLF injection. Versions 4.1.129.Final and 4.2.8.Final fix the issue.

Frequently asked questions

What is CVE-2025-67735?: Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.129.Final and 4.2.8.Final, the `io.netty.handler.codec.http.HttpRequestEncoder` has a CRLF injection with the request URI when constructing a request. This leads to request smuggling when `HttpRequestEncoder` is used without proper sanitization of the URI. Any application / framework using `HttpRequestEncoder` can be subject to be abused to perform request smuggling using CRLF injection. Versions 4.1.129.Final and 4.2.8.Final fix the issue.
How severe is CVE-2025-67735?: CVE-2025-67735 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 low, integrity low, and availability none.
Is CVE-2025-67735 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-67735?: CVE-2025-67735 affects Netty. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-67735?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-67735 have an EU (EUVD) identifier?: Yes. CVE-2025-67735 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-203450.
When was CVE-2025-67735 published?: CVE-2025-67735 was published on 2025-12-16 and last updated on 2026-06-17.

References

https://github.com/netty/netty/security/advisories/GHSA-84h7-rjj3-6jx4

Affected products (1)

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

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