# CVE-2026-3945: tinyproxy integer overflow in HTTP chunked transfer encoding

Source: https://junglewise.ai/threats/cve-2026-3945-tinyproxy-integer-overflow-in-http-chunked-transfer-encoding  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-03-30. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-3945 · Severity: high · CVSS 7.5 · Published 2026-03-30

tinyproxy is a lightweight HTTP proxy server used to forward and cache web traffic in corporate networks and embedded systems. An integer overflow flaw in its HTTP request parser allows a remote attacker to crash the proxy service by sending specially crafted HTTP requests, causing denial of service and disrupting network connectivity for downstream clients.

Technologies: [Tinyproxy](https://junglewise.ai/threats/technologies/tinyproxy). Vendors: [Tinyproxy](https://junglewise.ai/threats/vendors/tinyproxy).

## Quick answers

**Is CVE-2026-3945 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-3945 being exploited in the wild.

**How severe is CVE-2026-3945?** High severity, with a CVSS score of 7.5, published 30 March 2026.

**Which products and versions are affected?** Tinyproxy up to and including 1.11.3.

**Is there a fix for CVE-2026-3945?** A patch was published on 2026: Fixed in commits 969852c and bb7edc4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-3945 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-3945?** Check whether you run Tinyproxy at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an integer overflow in the HTTP chunked transfer encoding parser (pull_client_data_chunked function in src/reqs.c). The chunk size is parsed using strtol() without validating overflow conditions (errno == ERANGE) or negative values. An unauthenticated remote attacker can send a malicious HTTP request with a crafted chunked transfer encoding header to trigger integer overflow, leading to memory corruption or process termination. The vulnerability requires network access to the proxy port but no authentication. Patches were released in commits 969852c (negative value check) and bb7edc4 (overflow prevention) to validate chunk length values before processing.

## Affected products

- tinyproxy tinyproxy up to and including 1.11.3

## Timeline

- 2026-03-30: disclosed
- 2026: patched: Fixed in commits 969852c and bb7edc4

## References

- [https://github.com/tinyproxy/tinyproxy/commit/969852c](https://github.com/tinyproxy/tinyproxy/commit/969852c)
- [https://github.com/tinyproxy/tinyproxy/commit/bb7edc4](https://github.com/tinyproxy/tinyproxy/commit/bb7edc4)

## Related threats

- [Tinyproxy access control bypass in hostname matching](https://junglewise.ai/threats/cve-2026-125371-tinyproxy-through-1-11-3-contains-an-access-control-bypass)
- [Tinyproxy authentication bypass in stathost detection](https://junglewise.ai/threats/cve-2026-55202-tinyproxy-authentication-bypass-in-stathost-detection)
- [Tinyproxy HTTP request smuggling via duplicate Content-Length headers](https://junglewise.ai/threats/cve-2026-54388-tinyproxy-http-request-smuggling-via-duplicate-content-length)
- [Tinyproxy HTTP request smuggling in request header parsing](https://junglewise.ai/threats/cve-2026-54387-tinyproxy-http-request-smuggling-in-request-header-parsing)