nm-l2tp NetworkManager-l2tp up to 1.52.4 VPN Connection Properties write_config_option mru/mtu input validation

Summaryinfo

A vulnerability categorized as very critical has been discovered in nm-l2tp NetworkManager-l2tp up to 1.52.4. This affects the function write_config_option of the component VPN Connection Properties. Executing a manipulation of the argument mru/mtu can lead to input validation. This vulnerability is handled as CVE-2026-93337. It is possible to launch the attack on the local host. There is not any exploit available.

Detailsinfo

A vulnerability has been found in nm-l2tp NetworkManager-l2tp up to 1.52.4 and classified as very critical. This vulnerability affects the function write_config_option of the component VPN Connection Properties. The manipulation of the argument mru/mtu with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

NetworkManager-l2tp contains an improper input validation vulnerability that allows local users with VPN connection creation permissions to inject arbitrary pppd directives by supplying mru or mtu property values containing trailing non-numeric content after a valid integer. Attackers can exploit the verbatim write of unvalidated strings into the pppd options file via write_config_option() to inject the plugin directive, causing the privileged pppd process to load an attacker-controlled shared object and achieve arbitrary code execution as root.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-93337 since 09/17/2026. The exploitation appears to be easy. The attack needs to be approached locally. The exploitation needs additional levels of successful authentication. 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 09/17/2026).

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

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Productinfo

Vendor

• nm-l2tp

Name

• NetworkManager-l2tp

Version

• 1.52.0
• 1.52.1
• 1.52.2
• 1.52.3
• 1.52.4

Website

• Product: https://github.com/nm-l2tp/NetworkManager-l2tp/

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