CVE-2021-36776Network attack vector

Privilege escalation via forwarded impersonation headers

Published Apr 1, 2022 · Updated Sep 17, 2024

Improper access control in SUSE Rancher 2.5.0 through 2.5.9 allows remote authenticated users to impersonate arbitrary cluster users. The Steve API proxy fails to remove attacker-supplied Impersonate-* headers before forwarding requests to the Kubernetes API. Any authenticated Rancher account can therefore assume an administrator identity on a managed cluster and gain that identity's cluster permissions.

CVSS severity8.8
High
EPSS probability1.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in SUSE Rancher 2.5.0 through 2.5.9 allows remote authenticated users to impersonate arbitrary cluster users. The Steve API proxy fails to remove attacker-supplied Impersonate-* headers before forwarding requests to the Kubernetes API. Any authenticated Rancher account can therefore assume an administrator identity on a managed cluster and gain that identity's cluster permissions.

The record

CVE
CVE-2021-36776
Published
Apr 1, 2022
Updated
Sep 17, 2024
Vendor
NeuVector
Product
Rancher
Classifications
CWE-284, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Rancher <2.5.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

NeuVector · Rancherversion=Rancher <2.5.10

Published CVSS scores

8.8SUSECVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
6.5NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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