CVE-2026-19499

A flaw was found in glibc. The strfmon and strfmon_l functions are vulnerable to a buffer overflow when processing right-justified width padding. This occurs because an incorrect length is used for an internal memory operation, causing data to be written beyond its intended buffer. An attacker could exploit this by providing specially crafted input, potentially leading to arbitrary code execution or other severe impacts.

This Moderate impact buffer overflow in strfmon or strfmon_l within glibc occurs when an application uses right-justified width padding with a specific buffer size, leading to an out-of-bounds write. Exploitation requires a vulnerable application code path that processes attacker-controlled formatting input or uses a fixed susceptible formatting pattern, limiting its general exploitability in typical Red Hat deployments.

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.

This issue is reachable only through applications that call glibc strfmon or strfmon_l with right-justified width padding into an undersized destination buffer. Prefer avoiding those APIs, or ensure destination buffers are sized for the full formatted result including padding. Where monetary formatting is exposed to untrusted input, restrict access to trusted clients.