CVE-2026-31842: Tinyproxy HTTP request parsing desynchronization via case-sensitive Transfer-Encoding handling

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-07 · updated 2026-08-10
Weakness: CWE-444

Description

Tinyproxy through 1.11.3 is vulnerable to HTTP request parsing desynchronization due to a case-sensitive comparison of the Transfer-Encoding header in src/reqs.c. The is_chunked_transfer function uses strcmp to compare the header value against "chunked", even though RFC 7230 specifies that transfer-coding names are case-insensitive.

Affected products

tinyproxy: through 1.11.3

References

https://datatracker.ietf.org/doc/html/rfc7230
https://github.com/tinyproxy/tinyproxy
https://github.com/tinyproxy/tinyproxy/issues/604

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