GNU glibc up to 2.44 strfmon buffer overflow

Summaryinfo

A vulnerability was found in GNU glibc up to 2.44 and classified as problematic. Affected by this issue is the function strfmon. Executing a manipulation can lead to buffer overflow. The identification of this vulnerability is CVE-2026-19499. The attack can only be executed locally. There is no exploit available.

Detailsinfo

A vulnerability classified as problematic was found in GNU glibc up to 2.44. This vulnerability affects the function strfmon. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Calling strfmon and strfmon_l in the GNU C Library version 2.38 to 2.44 can write past the end of the caller-supplied output buffer when a conversion uses right-justified width padding. Exploitation requires an application code path that calls strfmon or strfmon_l with right-justified width padding into a destination buffer that is large enough for the padding to succeed but too small for the internal memmove call. The field width or format may be attacker-influenced or a fixed susceptible pattern in the caller. At the time of publication, no network-facing application impact is known.

The advisory is shared for download at sourceware.org. This vulnerability was named CVE-2026-19499 since 08/10/2026. The exploitation appears to be easy. The attack needs to be approached locally. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/14/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Software Library

Vendor

• GNU

Name

• glibc

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.18
• 2.19
• 2.20
• 2.21
• 2.22
• 2.23
• 2.24
• 2.25
• 2.26
• 2.27
• 2.28
• 2.29
• 2.30
• 2.31
• 2.32
• 2.33
• 2.34
• 2.35
• 2.36
• 2.37
• 2.38
• 2.39
• 2.40
• 2.41
• 2.42
• 2.43
• 2.44

License

• open-source

Website

• Vendor: https://www.gnu.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion