Every CVE Search/ Get API key

CVE-2026-39429

kcp's cache server is accessible without authentication or authorization checks

8.2 HighFix available

kcp is a Kubernetes-like control plane for form-factors and use-cases beyond Kubernetes and container workloads. Prior to 0.30.3 and 0.29.3, the cache server is directly exposed by the root shard and has no authentication or authorization in place. This allows anyone who can access the root shard to read and write to the cache server. This vulnerability is fixed in 0.30.3 and 0.29.3.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
Low
Availability
None

Exploit likelihood

0.44%Up 0.4 points since Apr 9, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.2

kcp's cache server is accessible without authentication or authorization checks

kcp is a Kubernetes-like control plane for form-factors and use-cases beyond Kubernetes and container workloads. Prior to 0.30.3 and 0.29.3, the cache server is directly exposed by the root shard and has no authentication or authorization in place. This allows anyone who can access the root shard to read and write to the cache server. This vulnerability is fixed in 0.30.3 and 0.29.3.

Record
CVE-2026-39429
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Weakness
CWE-862, CWE-302
Updated
2026-11-02
EUVDEUVD-2026-20607 8.2

kcp is a Kubernetes-like control plane for form-factors and use-cases beyond Kubernetes and container workloads. Prior to 0.30.3 and 0.29.3, the cache server is directly exposed by the root shard and has no authentication or authorization in place. This allows anyone who can access the root shard to read and write to the cache server. This vulnerability is fixed in 0.30.3 and 0.29.3.

Record
EUVD-2026-20607
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-3j3q-wp9x-585p 8.2

kcp's cache server is accessible without authentication or authorization checks

Summary

The cache server is directly exposed by the root shard and has no authentication or authorization in place. This allows anyone who can access the root shard to read and write to the cache server.

Details

The cache server is routed in the pre-mux chain in the shard code. The preHandlerChainMux is handled before any authn/authz in the cache server: https://github.com/kcp-dev/kcp/blob/aaf93d59cbcd0cefb70d94bd8959ce390547c4a2/pkg/server/config.go#L514-L518

This results in the cache server being proxied before any authn/authz in the handler chain takes place.

Attack Vectors

1. Unauthenticated Read Access (Primary)

An attacker can read all replicated resources from the cache without any credentials. This exposes:

| Category | Resources | Severity | Reason | |---|---|---|---| | RBAC | clusterroles, clusterrolebindings (filtered by annotation) | High | Only subset with internal.kcp.io/replicate annotation: access rules, APIExport bind/content rules, WorkspaceType use rules. Reveals permission structure for API access and tenancy. Roles/RoleBindings NOT replicated. | | Infrastructure | logicalclusters, shards | High | Reveals full cluster topology and shard configuration | | API surface | apiexports, apiexportendpointslices, apiresourceschemas | High | Reveals all exported APIs and their network endpoints | | Admission control | mutatingwebhookconfigurations, validatingwebhookconfigurations, validatingadmissionpolicies | High | Reveals admission policies, aids bypass | | Tenancy | workspacetypes | Medium | Reveals workspace structure | | Cache metadata | cachedobjects, cachedresources, cachedresourceendpointslices | Medium | Exposes cache state and resource endpoints |

2. Write Access with Race Condition (Secondary)

The cache server allows full CRUD operations. While injected objects are cleaned up by the replication controller, a race condition exists that could allow temporary privilege escalation.

The race window:

  1. Attacker POSTs a malicious ClusterRole + ClusterRoleBinding to the cache server
  2. Cache etcd watch fires and notifies two consumers in parallel: 2.1. The authorization informer (CacheKubeSharedInformerFactory) updates its in-memory store — the GlobalAuthorizer and WorkspaceContentAuthorizer now see the injected RBAC rules 2.2. The replication controller's informer enqueues a reconcile to its workqueue
  3. Replication controller worker dequeues, calls getLocalCopy() → not found, deletes the object

Between steps 2 and 3, any API request hitting the GlobalAuthorizer (global_authorizer.go:89-101) would evaluate RBAC against a store that includes the attacker's injected rules. The authorization informer and the replication controller share the same CacheKubeSharedInformerFactory (config.go:361), so the object is visible to authorization as soon as the informer cache updates — before the replication controller can process and delete it.

Practical exploitability is low — the window is sub-second, requiring the attacker to fire the privileged API request with precise timing. However, it could be automated in a tight loop. The workqueue rate limiter could also widen the window under load.

Self-healing mechanism: The replication controller acts as a self-healing mechanism. Objects injected into the cache are deleted almost instantly because:

Creating an object in cache triggers the cache informer Replication controller reconciles, calls getLocalCopy() → not found Controller calls deleteObject() on the cache copy (replication_reconcile.go:157-168)

Replicatable

Start a kcp root shard and query the cache server, e.g. with:

curl --insecure…
Record
GHSA-3j3q-wp9x-585p
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Weakness
CWE-302, CWE-306, CWE-862
Updated
2026-11-02
NVD 8.2

kcp is a Kubernetes-like control plane for form-factors and use-cases beyond Kubernetes and container workloads. Prior to 0.30.3 and 0.29.3, the cache server is directly exposed by the root shard and has no authentication or authorization in place. This allows anyone who can access the root shard to read and write to the cache server. This vulnerability is fixed in 0.30.3 and 0.29.3.

Record
CVE-2026-39429
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
CVSS 3.1
9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weakness
CWE-302, CWE-862
Updated
2026-11-02
OSV 8.2

kcp's cache server is accessible without authentication or authorization checks

kcp is a Kubernetes-like control plane for form-factors and use-cases beyond Kubernetes and container workloads. Prior to 0.30.3 and 0.29.3, the cache server is directly exposed by the root shard and has no authentication or authorization in place. This allows anyone who can access the root shard to read and write to the cache server. This vulnerability is fixed in 0.30.3 and 0.29.3.

Record
CVE-2026-39429
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Weakness
CWE-302, CWE-862
Updated
2026-11-02
OSVGHSA-3j3q-wp9x-585p 8.2

kcp's cache server is accessible without authentication or authorization checks

Summary

The cache server is directly exposed by the root shard and has no authentication or authorization in place. This allows anyone who can access the root shard to read and write to the cache server.

Details

The cache server is routed in the pre-mux chain in the shard code. The preHandlerChainMux is handled before any authn/authz in the cache server: https://github.com/kcp-dev/kcp/blob/aaf93d59cbcd0cefb70d94bd8959ce390547c4a2/pkg/server/config.go#L514-L518

This results in the cache server being proxied before any authn/authz in the handler chain takes place.

Attack Vectors

1. Unauthenticated Read Access (Primary)

An attacker can read all replicated resources from the cache without any credentials. This exposes:

| Category | Resources | Severity | Reason | |---|---|---|---| | RBAC | clusterroles, clusterrolebindings (filtered by annotation) | High | Only subset with internal.kcp.io/replicate annotation: access rules, APIExport bind/content rules, WorkspaceType use rules. Reveals permission structure for API access and tenancy. Roles/RoleBindings NOT replicated. | | Infrastructure | logicalclusters, shards | High | Reveals full cluster topology and shard configuration | | API surface | apiexports, apiexportendpointslices, apiresourceschemas | High | Reveals all exported APIs and their network endpoints | | Admission control | mutatingwebhookconfigurations, validatingwebhookconfigurations, validatingadmissionpolicies | High | Reveals admission policies, aids bypass | | Tenancy | workspacetypes | Medium | Reveals workspace structure | | Cache metadata | cachedobjects, cachedresources, cachedresourceendpointslices | Medium | Exposes cache state and resource endpoints |

2. Write Access with Race Condition (Secondary)

The cache server allows full CRUD operations. While injected objects are cleaned up by the replication controller, a race condition exists that could allow temporary privilege escalation.

The race window:

  1. Attacker POSTs a malicious ClusterRole + ClusterRoleBinding to the cache server
  2. Cache etcd watch fires and notifies two consumers in parallel: 2.1. The authorization informer (CacheKubeSharedInformerFactory) updates its in-memory store — the GlobalAuthorizer and WorkspaceContentAuthorizer now see the injected RBAC rules 2.2. The replication controller's informer enqueues a reconcile to its workqueue
  3. Replication controller worker dequeues, calls getLocalCopy() → not found, deletes the object

Between steps 2 and 3, any API request hitting the GlobalAuthorizer (global_authorizer.go:89-101) would evaluate RBAC against a store that includes the attacker's injected rules. The authorization informer and the replication controller share the same CacheKubeSharedInformerFactory (config.go:361), so the object is visible to authorization as soon as the informer cache updates — before the replication controller can process and delete it.

Practical exploitability is low — the window is sub-second, requiring the attacker to fire the privileged API request with precise timing. However, it could be automated in a tight loop. The workqueue rate limiter could also widen the window under load.

Self-healing mechanism: The replication controller acts as a self-healing mechanism. Objects injected into the cache are deleted almost instantly because:

Creating an object in cache triggers the cache informer Replication controller reconciles, calls getLocalCopy() → not found Controller calls deleteObject() on the cache copy (replication_reconcile.go:157-168)

Replicatable

Start a kcp root shard and query the cache server, e.g. with:

curl --insecure…
Record
GHSA-3j3q-wp9x-585p
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Weakness
CWE-302, CWE-306, CWE-862
Updated
2026-11-02
OSVGO-2026-5088 No score

kcp's cache server is accessible without authentication or authorization checks in github.com/kcp-dev/kcp

kcp's cache server is accessible without authentication or authorization checks in github.com/kcp-dev/kcp

Record
GO-2026-5088
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/kcp-dev/kcp
Go
 0.30.0 up to 0.30.3
0.30.3
github.com/kcp-dev/kcp
Go
 before 0.29.3
0.29.3
github.com/kcp-dev/kcp
Go
 before 0.29.3, 0.30.0 up to 0.30.3
0.29.30.30.3
govulncheck-vulndb
openSUSE:Leap 16.0
 before 0.0.20260723T184607-160000.1.1
0.0.20260723T184607-160000.1.1

History

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

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

In short

CVE-2026-39429 is a high vulnerability (CVSS 8.2) in Kcp, published April 8, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.44%, the 37th percentile. Fixed in github.com/kcp-dev/kcp 0.30.3.

References

Show 194 moreShow less
This page doesn't list everything

Left out here: 1,541 references and the rest of 3 source descriptions. The JSON record has them.

Pages All vulnerabilities Browse Docs Sources Guide Get API key
MoveEnter Open