Security Digest · Vulnerability record
CVE-2021-25320: Rancher cloud credentials can be used through proxy API by users without access
A Improper Access Control vulnerability in Rancher, allows users in the cluster to make request to cloud providers by creating requests with the cloud-credential ID.
CVSS 9.9 Critical EPSS 0.9% · p58
Should you act?
Critical, preconditions apply
Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.9%, percentile 58: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 58% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes
github.com/rancher/rancher(Go) >= 2.2.0, < 2.4.16, fixed in 2.4.16;github.com/rancher/rancher(Go) >= 2.5.0, < 2.5.9, fixed in 2.5.9. Check your lockfile, including transitive dependencies.
What it is
A Improper Access Control vulnerability in Rancher, allows users in the cluster to make request to cloud providers by creating requests with the cloud-credential ID. Rancher in this case would attach the requested credentials without further checks This issue affects: Rancher versions prior to 2.5.9; Rancher versions prior to 2.4.16.
From the GitHub advisory
A vulnerability was discovered in Rancher 2.2.0 through the aforementioned patched versions, where cloud credentials weren't being properly validated through the Rancher API. Specifically through a proxy designed to communicate with cloud providers. Any Rancher user that was logged-in and aware of a cloud-credential ID that was valid for a given cloud provider, could call that cloud provider's API through the proxy API, and the cloud-credential would be attached. The exploit is limited to valid Rancher users. There is not a direct mitigation outside of upgrading to the patched Rancher versions.
Weakness type: CWE-284.
Product: github.com/rancher/rancher (Go) · Assigned by: suse · Published: 2021-07-15
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | github.com/rancher/rancher | >= 2.2.0, < 2.4.16 | 2.4.16 |
| Go | github.com/rancher/rancher | >= 2.5.0, < 2.5.9 | 2.5.9 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Rancher | Rancher | Rancher < 2.5.9 |
| Rancher | Rancher | Rancher < 2.4.16 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| suse | 3.1 | 9.9 Critical | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| GitHub | 3.1 | 9.9 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- FIRST EPSS (model of 2026-10-21): 0.85% probability of exploitation activity in the next 30 days; percentile 58.
Timeline
- — CVE record published by suse
- — CVE record last updated
- — GitHub-reviewed advisory GHSA-gqf8-rvrh-g7w6 published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-gqf8-rvrh-g7w6 github.com
- CVE.org record CVE-2021-25320 cve.org
- NVD entry CVE-2021-25320 nvd.nist.gov
Other references from the CVE record and advisory
- bugzilla.suse.com bugzilla.suse.com
- github.com github.com