CVE-2026-19499
Medium
Elevated severity or exploit probability.
CVSS base
7.7
HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:H
EPSS — probability of exploitation (30 days)
0.3%
19.9th percentile
CISA KEV
Not listed
Weakness / dates
CWE-122
Published 2026-09-14 · modified 2026-09-18
Description
Calling strfmon and strfmon_l in the GNU C Library version 2.38 to 2.44 can write past the end of the caller-supplied output buffer when a conversion uses right-justified width padding. Exploitation requires an application code path that calls strfmon or strfmon_l with right-justified width padding into a destination buffer that is large enough for the padding to succeed but too small for the internal memmove call. The field width or format may be attacker-influenced or a fixed susceptible pattern in the caller. At the time of publication, no network-facing application impact is known.