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Vulnerability record · CVE-2026-19499 · published 14 September 2026

CVE-2026-19499: Heap-based buffer overflow vulnerability

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.

7.7 CVSS 3.1 High EPSS 0.30% · top 79.9% CWE-122 · Heap-based buffer overflow Awaiting Analysis
7.7CVSS 3.1 base score
0.30%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
18 Sep 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:H

References

LinkTags
https://sourceware.org/bugzilla/show_bug.cgi?id=34510
https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0017

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Source: NIST National Vulnerability Database (record CVE-2026-19499), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.