actix-http has HTTP/1.1 CL.TE Request Smuggling

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

A vulnerability in actix-http's HTTP/1.1 request parser allows an unauthenticated remote client to smuggle requests in deployments where a front-end HTTP intermediary and the Actix backend disagree about whether Content-Length or Transfer-Encoding: chunked defines the request body length. Severity Medium. This is an HTTP request smuggling vulnerability that can be triggered over the network without application-level credentials. Exploitation requires a specific proxy topology: an upstream proxy, WAF, load balancer, or similar intermediary must use Content-Length framing while forwarding the conflicting Transfer-Encoding: chunked request to an Actix backend over a reused HTTP/1.1 connection. Affected Versions - actix-http: versions up to and including 3.12.0 Description HTTP/1.1 requests that contain both Content-Length and Transfer-Encoding: chunked are ambiguous and must be rejected by recipients to avoid request smuggling. Affected versions of actix-http accepted a request with a…

Published by the source

22 Apr 2026, 14:37 UTC

Last modified by the source

22 Apr 2026, 14:37 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-xhj4-vrgc-hr34

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# Patch Next advisory brief: GHSA-xhj4-vrgc-hr34

Advisory: actix-http has HTTP/1.1 CL.TE Request Smuggling
IDs: GHSA-xhj4-vrgc-hr34
Record: https://patchnext.com/advisories/ghsa-xhj4-vrgc-hr34 (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: actix-http 3.12.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io actix-http: affected < 3.12.1; fixed in 3.12.1

## Suggested inspection (read-only)
- crates.io actix-http: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on actix-http.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-xhj4-vrgc-hr34 (GitHub-reviewed advisory GHSA-xhj4-vrgc-hr34 lists affected ranges: crates.io actix-http >=0 <3.12.1)

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