CVE-2026-102474: Dash: dash: heap out-of-bounds write in conv_escape via undersized unicode escape reservation

Severity: medium (CVSS 4.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-29 · updated 2026-09-29
Weakness: CWE-787

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.

References

https://access.redhat.com/security/cve/CVE-2026-102474
https://bugzilla.redhat.com/show_bug.cgi?id=2543004

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