What’s Vulnerable › Vulnerabilities

CVE-2026-5450: scanf %mc off-by-one heap buffer overflow

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-04-20 · updated 2026-07-14
• Weakness: CWE-122

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.

Affected products

• GNU C Library (glibc): from 2.7 through 2.43

References

• https://inbox.sourceware.org/libc-announce/b11f0003-6ec1-4bd6-b9de-9e38a4efeca3@redhat.com/T/#u
• https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450
• https://cert-portal.siemens.com/productcert/html/ssa-082556.html
• https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450

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