scanf %mc off-by-one heap buffer overflow_CVE-2026-5450

9.8 / 10

CRITICAL

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

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.

AI Analysis

Off-by-one heap buffer overflow in scanf function

Basic Information

ID CVE-2026-5450

Source glibc

Published Apr 20, 2026 at 20:55

Modified Apr 21, 2026 at 19:49

Affected Product

Vendor The GNU C Library

Product glibc

Version 2.7

Affected Versions The GNU C Library glibc 2.7

CWE Classification

CWE-122

AI Assessment

AI Score 9.8 / 10

AI Severity Critical

Vendor GNU

Product GNU C Library

Version 2.7-2.43

References

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    "published": "2026-04-20T20:55:41.170Z",
    "modified": "2026-04-21T19:49:53.221Z",
    "type": "cve",
    "title": "scanf %mc off-by-one heap buffer overflow",
    "source": "glibc",
    "references": "https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450\nhttps://inbox.sourceware.org/libc-announce/[email protected]/T/#u",
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