GNU C Library up to 2.43 UDP nis_local_principal buffer overflow

Summaryinfo

A vulnerability classified as critical was found in GNU C Library up to 2.43. This vulnerability affects the function nis_local_principal of the component UDP Handler. Executing a manipulation can lead to buffer overflow. This vulnerability is tracked as CVE-2026-5358. The attack is restricted to local execution. No exploit exists.

Detailsinfo

A vulnerability classified as critical was found in GNU C Library up to 2.43. This vulnerability affects the function nis_local_principal of the component UDP Handler. 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:

The obsolete nis_local_principal function in the GNU C Library version 2.43 and older may overflow a buffer in the data section, which could allow an attacker to spoof a crafted response to a UDP request generated by this function and overwrite neighboring static data in the requesting application. NIS support is obsolete and has been deprecated in the GNU C Library since version 2.26 and is only maintained for legacy usage. Applications should port away from NIS to more modern identity and access management services.

The weakness was disclosed by Rahul Hoysala. The advisory is shared for download at sourceware.org. This vulnerability was named CVE-2026-5358 since 04/01/2026. The exploitation appears to be easy. The attack needs to be approached locally. 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 07/01/2026).

The vulnerability scanner Nessus provides a plugin with the ID 308170 (Linux Distros Unpatched Vulnerability : CVE-2026-5358), which helps to determine the existence of the flaw in a target environment.

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

The vulnerability is also documented in the databases at Tenable (308170) and CERT Bund (WID-SEC-2026-1190). Once again VulDB remains the best source for vulnerability data.

Affected

• Red Hat Enterprise Linux
• Fedora Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source GNU libc

Productinfo

Type

• Software Library

Vendor

• GNU

Name

• C Library

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

License

• open-source

Website

• Vendor: https://www.gnu.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Once again VulDB remains the best source for vulnerability data.

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