Vulnerability · Published Mar 13, 2026 · Assigned by mitre
CVE-2025-71263
High 7.4
In plain English
A high-severity buffer overflow in UNIX from AT&T Bell Labs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| AT&T Bell Labs | UNIX | 4 |
Weakness: CWE-120 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://sigma-star.at/blog/2025/12/unix-v4-buffer-overflow/
- https://www.tuhs.org/pipermail/tuhs/2026-January/032991.html
- https://discuss.systems/@ricci/115747843169814700
- https://www.spinellis.gr/blog/20251223/
- http://www.openwall.com/lists/oss-security/2026/03/20/6
- http://www.openwall.com/lists/oss-security/2026/03/21/4