CVE-2021-31999 json
Rancher: Privilege escalation vulnerability via malicious Connection header
published 2021-07-15 5 y ago modified 2026-09-10 1 mo ago also GHSA-pvxj-25m6-7vqr , GO-2024-2778 , EUVD-2024-1271
- cvss
- 8.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.1%
- EPSS 1.1% chance of exploitation in 30 days, percentile 64%
- public exploits
- 0
- none known
Summary
A Reliance on Untrusted Inputs in a Security Decision vulnerability in Rancher allows users in the cluster to act as others users in the cluster by forging the "Impersonate-User" or "Impersonate-Group" headers. This issue affects: Rancher versions prior to 2.5.9. Rancher versions prior to 2.4.16.
Patch / fix
- go github.com/rancher/rancher 2.4.16, 2.5.9
- Rancher Rancher 2.5.9
- Rancher SUSE Linux Enterprise Server 15 2.4.16
Exploit prediction
1.05% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.5 | AV:N/AC:L/Au:S/C:P/I:P/A:P |
| GitHub | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/rancher/rancher | >=2.0.0, <2.4.16 >=2.5.0, <2.5.9 >=2.0.0+incompatible |
2.4.16 2.5.9 |
Affected products
- Rancher Rancher
- Rancher SUSE Linux Enterprise Server 15
Classification
- Weakness
-
- CWE-807 Reliance on Untrusted Inputs in a Security Decision
References
-
bugzilla.suse.com
/show_bug.cgi?id=1187084
web, issue-tracking, release-notes, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-31999
advisory
-
github.com
/rancher/rancher
package
-
pkg.go.dev
/vuln/GO-2024-2778
web
-
github.com
/advisories/GHSA-pvxj-25m6-7vqr
advisory
Sources
- CVE List CVE-2021-31999
- GitHub Advisory GHSA-pvxj-25m6-7vqr
- NVD CVE-2021-31999
- OSV GO-2024-2778
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.