CVE-2026-66752

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.

References

• https://github.com/theopaid/HTTP-Request-Smuggling-via-Unparsed-Transfer-Encoding-Values-tiny_http-/tree/master
• https://www.vulncheck.com/advisories/tiny-http-http-request-smuggling-via-transfer-encoding-handling
• https://github.com/theopaid/HTTP-Request-Smuggling-via-Unparsed-Transfer-Encoding-Values-tiny_http-/tree/master