Description
A flaw was found in dash. The printf builtin reserves four bytes before converting a Unicode \u or \U escape, but the multi-byte token can need five or six bytes. A local user who can supply such an escape to dash printf or echo %b, including through dash -c and a positional argument, can write one or two bytes past that reservation.
References2
Metrics
- CVSS 3.1
-
4.0
MEDIUM
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - EPSS — exploit probability
- 0% percentile: 1 · as of 9 November 2026
- CWE
- CWE-787
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.