GHSA-xhj4-vrgc-hr34

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Source
https://github.com/advisories/GHSA-xhj4-vrgc-hr34
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-xhj4-vrgc-hr34/GHSA-xhj4-vrgc-hr34.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-xhj4-vrgc-hr34
Aliases
Downstream
CGA (4)
Published
2026-04-22T14:37:30Z
Modified
2026-09-10T03:51:04Z
Severity
  • 6.3 (Medium) CVSS_V4 - 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 CVSS Calculator
Summary
actix-http has HTTP/1.1 CL.TE Request Smuggling
Details

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 syntactically valid Content-Length header and Transfer-Encoding: chunked on the same HTTP/1.1 message. The parser then selected chunked decoding instead of rejecting the conflicting framing signals.

In a CL.TE proxy topology, an intermediary may treat bytes after the declared Content-Length body as part of the first request, while the Actix backend stops at the terminating chunk marker and parses the remaining bytes on the backend connection as a second HTTP request. This creates a backend-side request desynchronization primitive.

The issue is limited to HTTP/1.1 request parsing.

Impact

HTTP request smuggling

  • Attack Vector: Network, unauthenticated.
  • Effect: Backend request desynchronization with low integrity impact to requests processed by the vulnerable Actix service.
  • Scope: Actix services using affected actix-http versions behind an HTTP/1.1 intermediary that forwards ambiguous Content-Length plus Transfer-Encoding: chunked requests and reuses backend connections.

No direct confidentiality, availability, or subsequent-system impact is scored for this advisory.

Fixed Versions

This issue is fixed in actix-http 3.12.1.

The fix rejects HTTP/1.1 requests that contain both Content-Length and Transfer-Encoding: chunked instead of choosing one framing interpretation.

Mitigation

Users should upgrade to actix-http 3.12.1 or later.

Applications that depend on actix-http through actix-web, awc, or another Actix crate should ensure dependency resolution selects actix-http 3.12.1 or later. For example:

cargo update -p actix-http

If an immediate upgrade is not possible, configure all upstream HTTP intermediaries to reject HTTP/1.1 requests that contain both Content-Length and Transfer-Encoding, and avoid forwarding ambiguous request framing to Actix backends.

Credits

Actix thanks mufeedvh who disclosed this issue through coordinated disclosure.

Database specific 
{
    "cwe_ids":  [
        "CWE-444"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-04-22T14:37:30Z",
    "nvd_published_at":  null,
    "severity":  "MODERATE"
}
References

Affected packages

crates.io / actix-http

Package

Name
actix-http
View open source insights on deps.dev
Purl
pkg:cargo/actix-http

Affected ranges

Type
SEMVER
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
3.12.1

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-xhj4-vrgc-hr34/GHSA-xhj4-vrgc-hr34.json"