What is CVE-2026-5450?

CVE-2026-5450 is a critical-severity vulnerability in GNU Glibc, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-04-20.

How severe is CVE-2026-5450?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in GNU Glibc

CVE-2026-5450

Calling the scanf family of functions with a %mc (malloc'd character match) in the GNU C Library version 2.7 to version 2.43 with a format width specifier with an explicit width greater than 1024 could result in a one byte heap buffer overflow.

Vulnerability class: Buffer Overflow

Published 2026-04-20 · last modified 2026-07-14.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (53.0th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.007 · change: +0.002

Affected products

GNU Glibc
The GNU C Library Glibc — versions 2.7

Weakness classification (CWE)

References

3ff69d7a-14f2-4f67-a097-88dee7810d18 (issue-tracking, Exploit, Issue Tracking)
3ff69d7a-14f2-4f67-a097-88dee7810d18 (mailing-list, Third Party Advisory)
0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

Frequently asked questions

What is CVE-2026-5450?: CVE-2026-5450 is a critical-severity vulnerability in GNU Glibc, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-04-20.
How severe is CVE-2026-5450?: Critical severity. CVSS v3 base score is 9.8 out of 10.