CVE-2026-41417
Netty ≤ 4.1.133
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NSummary
CVE-2026-41417 is a medium-severity CRLF Injection (CWE-93) vulnerability in Netty Netty. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 23th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-28224
Vulnerability Data
Netty allows request-line validation to be bypassed when a `DefaultHttpRequest` or `DefaultFullHttpRequest` is created first and its URI is later changed via `setUri()`. The constructors reject CRLF and whitespace characters that would break the start-line, but `setUri()` does not apply…
more
the same validation. `HttpRequestEncoder` and `RtspEncoder` then write the URI into the request line verbatim. If attacker-controlled input reaches `setUri()`, this enables CRLF injection and insertion of additional HTTP or RTSP requests, leading to HTTP request smuggling or desynchronization on the HTTP side and request injection on the RTSP side. This issue is fixed in versions 4.2.13.Final and 4.1.133.Final.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability in Netty HTTP/RTSP request handling directly enables CRLF injection and request smuggling when attacker input reaches setUri(), facilitating exploitation of public-facing applications.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation of untrusted input (the URI passed to setUri) to reject CRLF and other illegal characters before they reach the encoder.
Mandates prompt application of the vendor patches (4.1.133.Final / 4.2.13.Final) that close the setUri validation bypass.
Boundary-protection devices can enforce strict HTTP/RTSP message parsing and reject smuggling attempts that originate from the flawed Netty component.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Configuration management can enforce uniform HTTP parsing rules across intermediaries, directly mitigating inconsistent interpretation.
Secure SDLC practices directly require input neutralization and validation to block CRLF injection.
Network monitoring can detect smuggling attempts via anomalous HTTP traffic or logs, while eliminating the inconsistency directly aids detection of such events.
Network protections can enforce consistent HTTP proxy/firewall behavior to block smuggling, and removing the weakness helps prevent unauthorized access via request smuggling.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect CRLF flaws but does not itself implement the neutralization.
Network security controls can enforce consistent HTTP parsing and proxy behavior that mitigates request smuggling.
Secure network services include hardening proxies and gateways against inconsistent HTTP interpretation.
Secure development lifecycle mandates input validation and output encoding that directly prevents CRLF injection.
Application security requirements include rules for neutralizing special characters such as CRLF in inputs.
Secure architecture principles encourage safe handling of untrusted data but do not prescribe specific CRLF controls.