CVE-2026-73051: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in actix actix-web
actix-http versions before 3.12.1 contain an HTTP request smuggling vulnerability in the HTTP/1.1 parser that accepts requests with both Content-Length and Transfer-Encoding: chunked headers. Unauthenticated remote attackers can exploit this through a front-end intermediary to desynchronize backend requests and smuggle malicious HTTP requests to the Actix service.
AI Analysis
Technical Summary
CVE-2026-73051 is an HTTP request smuggling vulnerability in actix-http's HTTP/1.1 parser affecting versions prior to 3.12.1. The parser incorrectly accepts requests that include both Content-Length and Transfer-Encoding: chunked headers, enabling attackers to cause desynchronization between front-end intermediaries and backend servers. This can be exploited remotely without authentication to smuggle malicious HTTP requests to the backend Actix service, potentially bypassing security controls or causing unintended behavior.
Potential Impact
The vulnerability allows unauthenticated remote attackers to exploit front-end intermediaries to desynchronize backend requests, enabling HTTP request smuggling attacks against the Actix service. This could lead to unauthorized request injection or manipulation, impacting the integrity and reliability of HTTP communications handled by the affected versions of actix-http.
Mitigation Recommendations
A fix is available in actix-http version 3.12.1 and later. Users should upgrade to version 3.12.1 or newer to remediate this vulnerability. Patch status is inferred from the affected versions and the version where the vulnerability is fixed; no official vendor advisory was provided in the input. Until upgraded, users should consider mitigating exposure by restricting or validating HTTP headers at front-end intermediaries if possible.
CVE-2026-73051: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') in actix actix-web
Description
actix-http versions before 3.12.1 contain an HTTP request smuggling vulnerability in the HTTP/1.1 parser that accepts requests with both Content-Length and Transfer-Encoding: chunked headers. Unauthenticated remote attackers can exploit this through a front-end intermediary to desynchronize backend requests and smuggle malicious HTTP requests to the Actix service.
CVSS v4.0
Score 6.3medium
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-73051 is an HTTP request smuggling vulnerability in actix-http's HTTP/1.1 parser affecting versions prior to 3.12.1. The parser incorrectly accepts requests that include both Content-Length and Transfer-Encoding: chunked headers, enabling attackers to cause desynchronization between front-end intermediaries and backend servers. This can be exploited remotely without authentication to smuggle malicious HTTP requests to the backend Actix service, potentially bypassing security controls or causing unintended behavior.
Potential Impact
The vulnerability allows unauthenticated remote attackers to exploit front-end intermediaries to desynchronize backend requests, enabling HTTP request smuggling attacks against the Actix service. This could lead to unauthorized request injection or manipulation, impacting the integrity and reliability of HTTP communications handled by the affected versions of actix-http.
Mitigation Recommendations
A fix is available in actix-http version 3.12.1 and later. Users should upgrade to version 3.12.1 or newer to remediate this vulnerability. Patch status is inferred from the affected versions and the version where the vulnerability is fixed; no official vendor advisory was provided in the input. Until upgraded, users should consider mitigating exposure by restricting or validating HTTP headers at front-end intermediaries if possible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-10T19:10:18.100Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a7f0286bf8831d539fec91f
Added to database: 08/14/2026, 11:56:54 UTC
Last enriched: 08/14/2026, 12:12:05 UTC
Last updated: 08/14/2026, 16:55:07 UTC
Views: 7
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