CVE-2026-66752 tiny-http 0.12.0 HTTP Request Smuggling via Transfer-Encoding Handling
Attackers can desynchronize request framing or exhaust worker threads in tiny-http by exploiting improper Transfer-Encoding header handling.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66752?
CVE-2026-66752 is a medium-severity vulnerability in tiny-http, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
tiny-http through 0.12.0 contains an HTTP request smuggling vulnerability that allows remote attackers to desynchronize request framing by sending a Transfer-Encoding header with any value, including non-chunked codings, which causes the library to unconditionally apply chunk-decoding and discard Content-Length. Attackers can exploit the discrepancy between tiny_http's improper Transfer-Encoding parsing and a correctly-implemented front-end proxy to produce two distinct interpretations of a single byte stream, enabling request smuggling, and can additionally send non-chunked bodies with non-chunked Transfer-Encoding values to cause failed body reads that tie up connections and consume worker threads without signaling errors to clients.
Weakness: CWE-444
Which versions are affected by CVE-2026-66752?
How do I fix CVE-2026-66752?
No fix has been published for CVE-2026-66752 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-66752 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66752 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as DEBIAN-CVE-2026-66752, GHSA-5hc2-r3jq-vc45, UBUNTU-CVE-2026-66752.