Tinyproxy HTTP request parsing desynchronization via case-sensitive Transfer-Encoding handling
Priority HIGH 77CWE-444Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
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.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00585 48th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Tinyproxy Project | Tinyproxy | up to 1.11.3 | — | No fix listed | CNA |
- Tinyproxy VendorTinyproxy Project Affected up to 1.11.3 Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:tinyproxy_project:tinyproxy:*:*:*:*:*:*:*:* | up to 1.11.3 | Vulnerable | Tinyproxy Project |
- cpe:2.3:a:tinyproxy_project:tinyproxy:*:*:*:*:*:*:*:* Versions up to 1.11.3 Vulnerable ·Tinyproxy Project
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-31842
- 2026-10-03 Alias added: GHSA-mh87-c4c3-cgwf
- 2026-10-25 EPSS moved to the below the 50th percentile
References
More Tinyproxy Project Tinyproxy vulnerabilities
- TI-2023-27093 Use after free in Tinyproxy CVSS 3.1CRITICAL 9.8
- TI-2022-19200 Potential leak of left-over heap data if custom error page templates containing special… CVSS 3.1HIGH 7.5
- TI-2025-39495 Tinyproxy through 1.11.2 contains an integer overflow vulnerability in the… CVSS 3.1MEDIUM 6.5
- TI-2017-08702 main.c in Tinyproxy 1.8.4 and earlier creates a /run/tinyproxy/tinyproxy.pid file after… CVSS 3.0MEDIUM 5.5
Sources
- CVE-2026-31842 · CVE Program
- CVE-2026-31842 · NVD
- FIRST EPSS
- GHSA-mh87-c4c3-cgwf · GitHub Advisory Database · CC BY 4.0
- CVE-2026-31842 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences