Description
yaws before 2.0.4 does not attempt to address RFC 3875 section 4.1.18 namespace conflicts and therefore does not protect CGI applications from the presence of untrusted client data in the HTTP_PROXY environment variable, which might allow remote attackers to redirect a CGI application's outbound HTTP traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, aka an "httpoxy" issue.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | yaws | 2.0.3-2 | — |
| Debian 13 | yaws | 2.0.3-2 | — |
| Debian 12 | yaws | 2.0.3-2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | yaws | No fix yet | — |
Advisories 1
- WID-SEC-2025-2522 Mehrere Webserver: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Nov 10, 2025
References
- https://raw.githubusercontent.com/distributedweaknessfiling/cvelist/master/2016/1000xxx/CVE-2016-1000108.json
- http://www.openwall.com/lists/oss-security/2016/07/18/6
- https://security-tracker.debian.org/tracker/CVE-2016-1000108
- https://github.com/klacke/yaws/commit/9d8fb070e782c95821c90d0ca7372fc6d7316c78#diff-54053c47eb173a90c26ed19bd9d106c1