Vulnerability Description
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.
CVSS Score
HIGH
Related Weaknesses (CWE)
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
FAQ
What is CVE-2025-71263?
CVE-2025-71263 is a vulnerability with a CVSS score of 7.4 (HIGH). 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 priv...
How severe is CVE-2025-71263?
CVE-2025-71263 has been rated HIGH with a CVSS base score of 7.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-71263?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.