CVE-2026-31842
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.57%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.57% probability · 46th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-444
- Affected
- tinyproxy project/tinyproxy
- Source
- 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
References
- https://datatracker.ietf.org/doc/html/rfc7230Exploit, Technical Description
- https://github.com/tinyproxy/tinyproxyProduct
- https://github.com/tinyproxy/tinyproxy/issues/604Exploit, Issue Tracking
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.