Vulnerability Details CVE-2025-71263
In UNIX Fourth Research Edition (v4), the su command is vulnerable to a buffer overflow due to the 'password' variable having a fixed size of 100 bytes. A local user can exploit this to gain root privileges. It is unlikely that UNIX v4 is running anywhere outside of a very small number of lab environments. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 7.6%
CVSS Severity
CVSS v3 Score 7.4
References
- https://discuss.systems/@ricci/115747843169814700
- https://sigma-star.at/blog/2025/12/unix-v4-buffer-overflow/
- https://www.spinellis.gr/blog/20251223/
- https://www.tuhs.org/pipermail/tuhs/2026-January/032991.html
- http://www.openwall.com/lists/oss-security/2026/03/20/6
- http://www.openwall.com/lists/oss-security/2026/03/21/4