UpHeron
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Servers and applications

CVE-2021-31999

Privilege escalation vulnerability via malicious "Connection" header

Severity
High 8.8
Published
15 Jul 2021
Last changed
17 Jun 2026
Added to UpHeron
1 Nov 2026
Fixed in
2.4.16, 2.5.9
Also known as
GHSA-pvxj-25m6-7vqr
Sources
NVD, Project advisories (GitHub)

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.

Affected software

SoftwareAffected versions
RancherServers and applications · cpe:a:rancher:rancher
  • Every version before 2.4.16
  • From 2.5.0 before 2.5.9
RancherServers and applications · github:rancher/rancher
  • Version 2.0.0+

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2021-31999
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2021-31999
  • GitHub Advisory Database https://github.com/advisories/GHSA-pvxj-25m6-7vqr
  • github.com https://github.com/rancher/rancher/security/advisories/GHSA-pvxj-25m6-7vqr