Description
CGI implementation in Yaws web server versions 1.81 to 2.0.7 is vulnerable to OS command injection.
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 | 2.0.8+dfsg-1 | — |
| Debian 13 | yaws | 2.0.8+dfsg-1 | — |
| Debian 12 | yaws | 2.0.8+dfsg-1 | — |
| Debian 10 | yaws | 2.0.6+dfsg-1+deb10u1 | DSA-4773-1 |
| Debian 9 | yaws | 2.0.4+dfsg-1+deb9u1 | DLA-2384-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | yaws | 2.0.4+dfsg-2ubuntu0.1 | USN-4569-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | yaws | 2.0.7+dfsg-1ubuntu0.1~esm1 | USN-8995-1 |
| Ubuntu Pro 16.04 LTS | yaws | 2.0.2-1ubuntu0.1~esm1 | USN-8995-1 |
Advisories 4
- USN-8995-1 yaws vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-4569-1 yaws vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-4773-1 yaws - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2384-1 yaws - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- https://github.com/erlyaws/yaws/commits/master
- https://packetstormsecurity.com/files/159106/Yaws-2.0.7-XML-Injection-Command-Injection.html
- https://vuln.be/post/yaws-xxe-and-shell-injections/
- https://github.com/vulnbe/poc-yaws-cgi-shell-injection
- [debian-lts-announce] 20200926 [SECURITY] [DLA 2384-1] yaws security update mailing-list
- USN-4569-1 vendor-advisory
- DSA-4773 vendor-advisory