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CVE-2026-41053

Over-inclusive team membership expansion in GitHub App authentication provider for Rancher

8.8 HighFix available

Incorrect authentication caching in the team member ship expansion of the Rancher Github authentication provider caused it granting principal access to any logged in user, in 2.13 before 2.13.6 and 2.14 before 2.14.2.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.52%Up 0.5 points since Jun 12, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.8

Over-inclusive team membership expansion in GitHub App authentication provider for Rancher

Incorrect authentication caching in the team member ship expansion of the Rancher Github authentication provider caused it granting principal access to any logged in user, in 2.13 before 2.13.6 and 2.14 before 2.14.2.

Record
CVE-2026-41053
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-303
Updated
2026-11-02
EUVDEUVD-2026-40297 8.8

Incorrect authentication caching in the team member ship expansion of the Rancher Github authentication provider caused it granting principal access to any logged in user, in 2.13 before 2.13.6 and 2.14 before 2.14.2.

Record
EUVD-2026-40297
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-4j6x-2764-m8gh 8.8

Rancher has over-inclusive team membership expansion in GitHub App authentication provider

Impact

A vulnerability has been identified within Rancher Manager in the GitHub App authentication provider. When evaluating permissions, the provider incorrectly expands user team memberships to include all teams within the associated GitHub organization, rather than restricting access to the specific teams to which the user actually belongs.

Specifically, when a user authenticates via the GitHub App provider, Rancher's team membership evaluation logic incorrectly handles cached data. Instead of checking the user-specific list, the evaluation logic iterates over all teams defined within the entire GitHub organization. The authentication provider should consult the correctly cached, per-user membership list to assign the user's specific group permissions. Consequently, any authenticated user who belongs to at least one team in a GitHub organization is mistakenly granted group principals for every team within that entire organization during authentication and authorization checks.

This issue allows a malicious user who is a member of a low-privilege team within a GitHub organization to gain unauthorized access to or permissions for any other team in that organization. If those other teams are bound to Rancher login allowlists or RBAC roles (cluster-level, project-level, or global), the attacker can pass access checks that should otherwise fail, inheriting permissions they were never granted.

Exploitation of this vulnerability requires the following conditions to be met:

  • The GitHub App authentication provider must be enabled and configured for the target GitHub organization.
  • The attacker must possess a valid GitHub account with membership in at least one team within that target organization.
  • A separate team within the same GitHub organization must be explicitly mapped to Rancher RBAC roles or specified within Rancher's login allowlist (allowedPrincipalIds).

Please consult the associated MITRE ATT&CK - Technique - Valid Accounts for further information about this category of attack.

Patches

This fix corrects the team listing logic to iterate only the teams stored in the per-user membership cache and includes a one-time startup migration that marks all affected User resources for refresh, forcing Rancher to rebuild group principals using the now-corrected logic.

Patched versions of Rancher include releases v2.14.2 and v2.13.6.

Workarounds

If upgrading to a patched version immediately is not feasible, users are encouraged to consider these temporary mitigations:

  • Disable GitHub App authentication provider and switch to an alternative authentication provider (GitHub OAuth).
  • Remove or restrict team-based group principals from allowed principalIds.
  • Audit and temporarily remove RBAC bindings (GlobalRoleBindings, ClusterRoleTemplateBindings, ProjectRoleTemplateBindings) that reference GitHub App team principals until the patch is applied.
  • Disable provider refresh and clean up inflated group membership for users (manually or by writing a script).

These workarounds reduce the attack surface but do not eliminate the vulnerability. Existing user sessions and cached principals remain inflated until a provider refresh occurs. Upgrading to a patched version is strongly recommended.

References

If you have any questions or comments about this advisory:

Record
GHSA-4j6x-2764-m8gh
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-303
Updated
2026-11-02
NVD 8.8

Incorrect authentication caching in the team member ship expansion of the Rancher Github authentication provider caused it granting principal access to any logged in user, in 2.13 before 2.13.6 and 2.14 before 2.14.2.

Record
CVE-2026-41053
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-303
Updated
2026-11-02
OSV 8.8

Over-inclusive team membership expansion in GitHub App authentication provider for Rancher

Incorrect authentication caching in the team member ship expansion of the Rancher Github authentication provider caused it granting principal access to any logged in user, in 2.13 before 2.13.6 and 2.14 before 2.14.2.

Record
CVE-2026-41053
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-303
Updated
2026-11-02
OSVGHSA-4j6x-2764-m8gh 8.8

Rancher has over-inclusive team membership expansion in GitHub App authentication provider

Impact

A vulnerability has been identified within Rancher Manager in the GitHub App authentication provider. When evaluating permissions, the provider incorrectly expands user team memberships to include all teams within the associated GitHub organization, rather than restricting access to the specific teams to which the user actually belongs.

Specifically, when a user authenticates via the GitHub App provider, Rancher's team membership evaluation logic incorrectly handles cached data. Instead of checking the user-specific list, the evaluation logic iterates over all teams defined within the entire GitHub organization. The authentication provider should consult the correctly cached, per-user membership list to assign the user's specific group permissions. Consequently, any authenticated user who belongs to at least one team in a GitHub organization is mistakenly granted group principals for every team within that entire organization during authentication and authorization checks.

This issue allows a malicious user who is a member of a low-privilege team within a GitHub organization to gain unauthorized access to or permissions for any other team in that organization. If those other teams are bound to Rancher login allowlists or RBAC roles (cluster-level, project-level, or global), the attacker can pass access checks that should otherwise fail, inheriting permissions they were never granted.

Exploitation of this vulnerability requires the following conditions to be met:

  • The GitHub App authentication provider must be enabled and configured for the target GitHub organization.
  • The attacker must possess a valid GitHub account with membership in at least one team within that target organization.
  • A separate team within the same GitHub organization must be explicitly mapped to Rancher RBAC roles or specified within Rancher's login allowlist (allowedPrincipalIds).

Please consult the associated MITRE ATT&CK - Technique - Valid Accounts for further information about this category of attack.

Patches

This fix corrects the team listing logic to iterate only the teams stored in the per-user membership cache and includes a one-time startup migration that marks all affected User resources for refresh, forcing Rancher to rebuild group principals using the now-corrected logic.

Patched versions of Rancher include releases v2.14.2 and v2.13.6.

Workarounds

If upgrading to a patched version immediately is not feasible, users are encouraged to consider these temporary mitigations:

  • Disable GitHub App authentication provider and switch to an alternative authentication provider (GitHub OAuth).
  • Remove or restrict team-based group principals from allowed principalIds.
  • Audit and temporarily remove RBAC bindings (GlobalRoleBindings, ClusterRoleTemplateBindings, ProjectRoleTemplateBindings) that reference GitHub App team principals until the patch is applied.
  • Disable provider refresh and clean up inflated group membership for users (manually or by writing a script).

These workarounds reduce the attack surface but do not eliminate the vulnerability. Existing user sessions and cached principals remain inflated until a provider refresh occurs. Upgrading to a patched version is strongly recommended.

References

If you have any questions or comments about this advisory:

Record
GHSA-4j6x-2764-m8gh
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-303
Updated
2026-11-02
OSVGO-2026-5869 No score

Rancher has over-inclusive team membership expansion in GitHub App authentication provider in github.com/rancher/rancher

Rancher has over-inclusive team membership expansion in GitHub App authentication provider in github.com/rancher/rancher.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: github.com/rancher/rancher from v2.13.0 before v2.13.6, from v2.14.0 before v2.14.2.

Record
GO-2026-5869
Updated
2026-11-02
OSVopenSUSE-SU-2026:21483-1 No score

Security update for govulncheck-vulndb

This update for govulncheck-vulndb fixes the following issues:

  • Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
  • GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
  • GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
  • GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
  • GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
  • GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
  • GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
  • GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
  • GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
  • GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
  • GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
  • GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
  • GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
  • GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
  • GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
  • GO-2026-5933 GHSA-3g4q-2f67-2gvh
  • GO-2026-5934 GHSA-59qp-cfj3-rp64
  • GO-2026-5935 GHSA-7856-g3gv-9wq8
  • GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
  • GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
  • GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
  • GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
  • GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
  • GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
  • GO-2026-5942 CVE-2026-46600
  • GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
  • GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
  • GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
  • GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
  • GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
  • GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
  • GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
  • GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
  • GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
  • GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
  • GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
  • GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
  • GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
  • GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
  • GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
  • GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
  • GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
  • GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
  • GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
  • GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
  • GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
  • GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
  • GO-2026-5969 GHSA-g936-7jqj-mwv8
  • GO-2026-5970 CVE-2026-56852
  • GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
  • GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
  • GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
  • GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
  • GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
  • GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
  • GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
  • GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
  • GO-2026-5981 GHSA-mqxv-9rm6-w8qc
  • GO-2026-5982 GHSA-pqg7-v6wh-3pfp
  • GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
  • GO-2026-5985 GHSA-7rx3-5wx3-5v76
  • GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
  • GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
  • GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
  • GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
  • GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
  • GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
  • GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
  • GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
  • GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
  • GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
  • GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
  • GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
  • GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
  • GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
  • GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
  • GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…
Record
openSUSE-SU-2026:21483-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
github.com/rancher/rancher
Go
 2.14.0 up to 2.14.2
2.14.2
github.com/rancher/rancher
Go
 2.13.0 up to 2.13.6
2.13.6
github.com/rancher/rancher
Go
 before 0.0.0-20260519172014-d0c047bbc6d2
0.0.0-20260519172014-d0c047bbc6d2
govulncheck-vulndb
openSUSE:Leap 16.0
From an advisory covering 1734 CVEs
 before 0.0.20260723T184607-160000.1.1
0.0.20260723T184607-160000.1.1

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-41053 is a high vulnerability (CVSS 8.8) in Suse Rancher, published June 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.52%, the 44th percentile. Fixed in github.com/rancher/rancher 2.14.2.

References

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Left out here: 1,543 references and the rest of 1 source description. The JSON record has them.

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