CVE-2026-91838: Command Injection (CVSS 7.8)

Description

A flaw was found in NetworkManager-sstp, the SSTP VPN plugin for NetworkManager. A local unprivileged user can exploit this vulnerability by embedding special characters, known as shell metacharacters, into VPN connection profile fields such as CA certificate or proxy settings. These unescaped characters are then processed by the `pppd` daemon, which runs with root privileges, allowing the attacker to execute arbitrary commands with elevated permissions when a malicious VPN connection is activated.

Is your site exposed to CVE-2026-91838?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0010

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-78 OS Command Injection

References

Other References

https://access.redhat.com/security/cve/CVE-2026-91838 https://bugzilla.redhat.com/show_bug.cgi?id=2533637 https://gitlab.gnome.org/GNOME/network-manager-sstp/-/work_items/67 https://gitlab.gnome.org/GNOME/network-manager-sstp/-/work_items/67

Frequently Asked Questions

What is CVE-2026-91838? +

A flaw was found in NetworkManager-sstp, the SSTP VPN plugin for NetworkManager. A local unprivileged user can exploit this vulnerability by embedding special characters, known as shell metacharacters, into VPN connection profile fields such as CA certificate or proxy settings. These unescaped characters are then processed by the `pppd` daemon, which runs with root privileges, allowing the attacker to execute arbitrary commands with elevated permissions when a malicious VPN connection is activated. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-91838? +

CVE-2026-91838 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0010, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-91838? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-102828

simple-git, an interface for running git commands in any node.js application, enables applications to execute Git operations from JavaScript. From …

CVE-2024-54012

Penetration Testing engineers at Amazon discovered a vulnerability where the camera system failed to properly validate input, allowing specially crafted …

CVE-2026-8652

An OS Command Injection vulnerability exists in Aterm. If a malicious third person gains administrator access to the product’s web …

CVE-2025-13605

3onedata modbus gateway device model GW1101-1D(RS-485)-TB-P (hardware version V2.2.0) allows authenticated users to execute arbitrary shell commands in the context …

CVE-2026-41925

WDR201A WiFi Extender (HW V2.1, FW LFMZX28040922V1.02) contains an OS command injection vulnerability in the adm.cgi binary's reboot_time function that …

CVE-2026-41924

WDR201A WiFi Extender (HW V2.1, FW LFMZX28040922V1.02) contains an OS command injection vulnerability in the makeRequest.cgi binary that allows unauthenticated …

CVE-2026-91838