CVE-2026-66752
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk15th percentile - higher than 15% of all known CVEs
Summary
tiny-http through version 0.12.0 contains an HTTP request smuggling vulnerability. Sending a Transfer-Encoding header with any value causes unconditional chunk-decoding and discarding of Content-Length, enabling desynchronization attacks.
Risk Assessment
An attacker can exploit the discrepancy in Transfer-Encoding parsing between tiny-http and a correctly-implemented proxy, leading to request smuggling, and can also cause connection blocking and worker thread exhaustion.
Recommendation
Update the tiny-http library to version 0.12.1 or later that fixes this vulnerability, or apply a workaround by rejecting non-standard Transfer-Encoding headers at the proxy level.
Other vulnerabilities in tiny-http
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS