HTTP Request Smuggling Affecting actix-http package, versions <3.12.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RUST-ACTIXHTTP-16301596
- published27 Apr 2026
- disclosed22 Apr 2026
- creditmufeedvh
Introduced: 22 Apr 2026
CVE-2026-73051 (opens in a new tab)How to fix?
Upgrade actix-http to version 3.12.1 or higher.
Overview
actix-http is a HTTP primitives for the Actix ecosystem
Affected versions of this package are vulnerable to HTTP Request Smuggling in the HTTP/1.1 request parsing process. An attacker can cause backend request desynchronization by sending specially crafted HTTP requests containing both Content-Length and Transfer-Encoding: chunked headers, which may be interpreted differently by intermediaries and the backend, leading to processing of unintended requests. This is only exploitable if an upstream HTTP intermediary (such as a proxy, WAF, or load balancer) forwards ambiguous requests with both headers to the backend over a reused HTTP/1.1 connection.
Workaround
This vulnerability can be mitigated by configuring all upstream HTTP intermediaries to reject HTTP/1.1 requests that contain both Content-Length and Transfer-Encoding, and by avoiding forwarding ambiguous request framing to backends.