How severe is CVE-2025-23389?

CVE-2025-23389 has a CVSS score of 8.4/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-23389?

CVE-2025-23389 affects the following packages: github.com/rancher/rancher (Go), github.com/rancher/rancher (Go), github.com/rancher/rancher (Go). Ecosystems affected: Go.

How do I fix CVE-2025-23389?

Update github.com/rancher/rancher to 2.8.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-23389 is resolved across your whole dependency graph.

How do I detect CVE-2025-23389 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/rancher/rancher, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-23389 if there is no patch (or I can't update yet)?

Close the privilege gap rather than the entry point: audit which accounts, roles and service identities can reach the affected operation, drop the component to the least privilege it actually needs, and review file and directory permissions created by earlier installs — a default left in place is what makes this reachable.

Is CVE-2025-23389 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-23389 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-23389?

CVE-2025-23389 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-23389?

CVE-2025-23389 is classified as CWE-284 (CWE-284). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-23389 published, and has it been updated?

CVE-2025-23389 was published on April 11, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

HIGH severity

CVE-2025-23389 — rancher

HIGHFix: rancher/rancher#48964

CVE-2025-23389 is a high-severity (CVSS 8.4) CWE-284 vulnerability in github.com/rancher/rancher. A fix is available for github.com/rancher/rancher — see the affected versions and patch details below.

Rancher does not Properly Validate Account Bindings in SAML Authentication Enables User Impersonation on First Login

Also known asGHSA-mq23-vvg7-xfm4GO-2025-3490

Published

Apr 11, 2025

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-23389.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk+0.01%

Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected

🐹github.com/rancher/rancher🐹github.com/rancher/rancher🐹github.com/rancher/rancher

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

A vulnerability in Rancher has been discovered, leading to a local user impersonation through SAML Authentication on first login.

The issue occurs when a SAML authentication provider (AP) is configured (e.g. Keycloak). A newly created AP user can impersonate any user on Rancher by manipulating cookie values during their initial login to Rancher. This vulnerability could also be exploited if a Rancher user (present on the AP) is removed, either manually or automatically via the User Retention feature with delete-inactive-user-after.

More precisely, Rancher validates only a subset of input from the SAML assertion request; however, it trusts and uses values that are not properly validated. An attacker could then configure the saml_Rancher_UserID cookie and the saml_Rancher_Action cookie so that the user principal from the AP will be added to the user specified by the attacker (from saml_Rancher_UserID). Rancher can then be deceived by setting saml_Rancher_UserID to the admin's user ID and saml_Rancher_Action to testAndEnable, thereby executing the vulnerable code path and leading to privilege escalation.

Note that the vulnerability impacts all SAML APs available in Rancher. However the following Rancher deployments are not affected:

Rancher deployments not using SAML-based AP.
Rancher deployments using SAML-based AP, where all SAML users are already signed in and linked to a Rancher account.

Please consult the associated MITRE ATT&CK - Technique - Access Token Manipulation: Token Impersonation/Theft for further information about this category of attack.

Patches

This vulnerability is addressed by adding the UserID claim to a JWT signed token, which is protected against tampering.

Patched versions include releases v2.8.13, v2.9.7 and v2.10.3.

Workarounds

Rancher deployments that can't upgrade, could temporarily disable the SAML-based AP as a temporary workaround. However, upgrading is recommended.

References

If you have any questions or comments about this advisory:

Reach out to the SUSE Rancher Security team for security related inquiries.
Open an issue in the Rancher repository.
Verify with our support matrix and product support lifecycle.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/rancher/rancher`	≥ 2.8.0&&< 2.8.13	2.8.13`go get github.com/rancher/rancher@v2.8.13`
🐹Go	`github.com/rancher/rancher`	≥ 2.9.0&&< 2.9.7	2.9.7`go get github.com/rancher/rancher@v2.9.7`
🐹Go	`github.com/rancher/rancher`	≥ 2.10.0&&< 2.10.3	2.10.3`go get github.com/rancher/rancher@v2.10.3`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/rancher/rancher, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/rancher/rancher to 2.8.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-23389 is resolved across your whole dependency graph.
Workarounds
Close the privilege gap rather than the entry point: audit which accounts, roles and service identities can reach the affected operation, drop the component to the least privilege it actually needs, and review file and directory permissions created by earlier installs — a default left in place is what makes this reachable.

Frequently Asked Questions

### Impact A vulnerability in Rancher has been discovered, leading to a local user impersonation through SAML Authentication on first login. The issue occurs when a SAML authentication provider (AP) is configured (e.g. Keycloak). A newly created AP user can impersonate any user on Rancher by manipulating cookie values during their initial login to Rancher. This vulnerability could also be exploited if a Rancher user (present on the AP) is removed, either manually or automatically via the [User Retention feature](https://ranchermanager.docs.rancher.com/how-to-guides/advanced-user-guides/enable

O3 Security · Impact-Aware SCA

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