Medium severity · published Dec 16, 2025
CVE-2025-67735
Netty has a CRLF Injection vulnerability in io.netty.handler.codec.http.HttpRequestEncoder
6.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NE
netty · netty
>= 4.2.0.Alpha1, < 4.2.8.Final; < 4.1.129.Final · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-67735
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-67735
Exploit
https://github.com/netty/netty/security/advisories/GHSA-84h7-rjj3-6jx4
More from netty
7.5
CVE-2023-44487
HTTP/2 Rapid Reset Attack Vulnerability
10.0
CVE-2026-47691
Netty has Insufficient Bailiwick Validation for NS Records
10.0
CVE-2026-45674
Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records
9.8
CVE-2026-56817
Netty: XML External Entity (XXE) injection via unconfigured XML factory when DTD and entity processing are enabled
9.8
CVE-2026-42581
Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization