CVE-2026-5450

Description

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.

CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0005

Probability of exploitation

0.15%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-122 CWE-122

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
gnu	glibc	2.7 — 2.43

References

Exploits

https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450 https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450

Other References

https://inbox.sourceware.org/libc-announce/[email protected]/T/#u

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-5450? +

CVE-2026-5450 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0005, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-5450? +

CVE-2026-5450 affects products from gnu, specifically: glibc. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-5450? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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