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GHSA-mc24-7m59-4q5p

HighCVSS 8.3 / 10
Published Feb 1, 2026·Last modified Feb 28, 2026
Affected Components(0)

No affected components available

Description

Impact

A vulnerability has been identified within Rancher Manager, where using self-signed CA certificates and passing the -skip-verify flag to the Rancher CLI login command without also passing the –cacert flag results in the CLI attempting to fetch CA certificates stored in Rancher’s setting cacerts. This does not apply to any other commands and only applies to the login command if the –cacert flag was not provided.

An attacker with network-level access between the Rancher CLI and Rancher Manager could interfere with the TLS handshake to return a CA they control, despite the use of the --skip-verify flag. This may be abused to bypass TLS as a security control. Attackers can also see basic authentication headers in a Man-in-the-Middle due to the lack of TLS enforcement.

Please consult the associated MITRE ATT&CK - Technique - Man-in-the-Middle for further information about this category of attack.

Patches

This vulnerability is addressed by removing the ability to fetch CA certificates stored in Rancher’s setting cacerts when using the login command. Whenever required, for example when using self-signed certificates, CA certificates have to be explicitly passed with the –cacert flag.

Patched versions of Rancher include releases v2.13.2, v2.12.6, v2.11.10, and v2.10.11.

Workarounds

If a projecct can't upgrade to a fixed version, please make sure whenever required, for example when using self-signed certificates, to always explicitly pass CA certificates with the –cacert flag when using the login command.

References

If there are any questions or comments about this advisory:

Note: Rancher versions beyond 2.3.0-alpha5 are no longer supported at pkg.go.dev, follow Rancher installation instructions for newer versions.

Risk Scores
Base Score
8.3

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
7.6

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.15%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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