CVE-2026-5450

A flaw was found in glibc (GNU C Library). This vulnerability occurs when an application uses the scanf family of functions with a %mc format specifier, which is used for dynamically allocating memory for character input, and provides an explicit width greater than 1024. This specific combination can lead to a one-byte heap buffer overflow, potentially allowing an attacker to corrupt memory.

Because this flaw requires that an affected application call the affected functions with an attacker-supplied value, Red Hat assesses the Attack Complexity of this flaw as High. Additionally, the flaw overflows a single byte onto the heap, so meaningful exploitation requires that the heap is structured such that a single byte can lead to an attacker-controlled outcome, or that the affected functions can be invoked with an attacker-controlled buffer base address. Regarding Attack Vector and Privileges Required, Red Hat assesses these elements as Local and Low respectively, as remote unauthenticated exploitation would require all the conditions above in a library client that listened on a network port and processed attacker-controllable data with the affected library functions.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.