CVE-2021-31999
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.05%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.05% probability · 64th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-807
- Affected
- rancher/rancher
- Source
- meissner@suse.de
EPSS 1.1% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.suse.com/show_bug.cgi?id=1187084Issue Tracking, Release Notes, Third Party Advisory
- https://bugzilla.suse.com/show_bug.cgi?id=1187084Issue Tracking, Release Notes, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.