Vulnerability · Published Aug 14, 2026 · Assigned by VulnCheck

CVE-2026-73051actix-http before 3.12.1 HTTP Request Smuggling via CL.TE

Medium 6.3

In plain English

A medium-severity security flaw in actix-http from actix. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.3Medium

Exploit odds (30 days)0.6%top 52.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:13	rust-actix-http	no fix listed	DEBIAN-CVE-2026-73051
Debian:14	rust-actix-http	3.13.1-1	DEBIAN-CVE-2026-73051
Ubuntu:26.04:LTS	rust-actix-http	no fix listed	UBUNTU-CVE-2026-73051
Ubuntu:26.10	rust-actix-http	no fix listed	UBUNTU-CVE-2026-73051

Affected products (as reported)

Vendor	Product	Versions
actix	actix-http	0 – before 3.12.1

Weakness: CWE-444 · Vector: 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

References

GitHub Security Advisory (GHSA-xhj4-vrgc-hr34) vendor-advisory
VulnCheck Advisory: actix-http before 3.12.1 HTTP Request Smuggling via CL.TE third-party-advisory