GNOME NetworkManager-vpnc VPN Username os command injection

Summaryinfo

A vulnerability was found in GNOME NetworkManager-vpnc. It has been classified as very critical. This affects an unknown part of the component VPN Username Handler. This manipulation of the argument Username causes os command injection. This vulnerability is handled as CVE-2026-91840. It is possible to launch the attack on the local host. There is not any exploit available.

Detailsinfo

A vulnerability classified as very critical was found in GNOME NetworkManager-vpnc (unknown version). Affected by this vulnerability is an unknown code block of the component VPN Username Handler. The manipulation of the argument username with an unknown input leads to a os command injection vulnerability. The CWE definition for the vulnerability is CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

A flaw was found in NetworkManager-vpnc. This vulnerability allows a local unprivileged user to escalate privileges to root. By injecting a newline character into the VPN username field, an attacker can manipulate the vpnc configuration to execute an arbitrary program with root privileges when the malicious VPN connection is activated.

The advisory is shared at access.redhat.com. This vulnerability is known as CVE-2026-91840 since 09/15/2026. The exploitation appears to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/25/2026). MITRE ATT&CK project uses the attack technique T1202 for this issue.

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

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• GNOME

Name

• NetworkManager-vpnc

License

• open-source

Website

• Vendor: https://www.gnome.org/

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion