{"id":"GHSA-cwxq-rc9x-2jvv","revision":null,"records":[{"revision":"cc76ed3c43134f4b9278f57df9d9b455","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-54247","aliases":[],"title":"Skipper: Unbounded Request Body Read in Admission Webhook Causes Memory Exhaustion DoS","description":"Skipper is an HTTP router and reverse proxy for service composition. Prior to 0.26.22, Handler in dataclients/kubernetes/admission/admission.go passes the body of requests to the Kubernetes admission endpoint at :9443/admission directly to io.ReadAll(r.Body) without a size limit. An attacker with in-cluster network access and a valid Kubernetes client certificate can send a very large body that causes unbounded memory allocation and an out-of-memory termination of the Skipper process. The disruption is limited to Ingress and RouteGroup admission rather than pod creation or unrelated admission controllers, and Kubernetes normally restarts the process. This issue is fixed in version 0.26.22.","state":0,"publishedAt":"2026-09-14T20:04:06.55+00:00","modifiedAt":"2026-09-16T16:19:12.336+00:00","affected":[{"ecosystem":"Vendor product","name":"skipper","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"zalando\",\n                    \"product\": \"skipper\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 0.26.22\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","score":4.3,"severity":"MEDIUM"}],"references":["https://github.com/zalando/skipper/security/advisories/GHSA-cwxq-rc9x-2jvv","https://github.com/zalando/skipper/pull/4053","https://github.com/zalando/skipper/commit/c3d156c6caaefecc9a46774c0f9c3c70b97160b4","https://github.com/zalando/skipper/releases/tag/v0.26.22"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-54247","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-54247","identifiers":["CVE-2026-54247"]},"retained":false,"historicalAffected":[]},{"revision":"cc40f44acc2f40c8a45c360e732d7bf0","observedAt":"2026-11-11T13:59:12.04+00:00","statement":{"source":"euvd","id":"EUVD-2026-78062","aliases":["CVE-2026-54247","GHSA-cwxq-rc9x-2jvv"],"title":"Skipper is an HTTP router and reverse proxy for service composition. Prior to 0.26.22, Handler in dataclients/kubernetes/admission/admission.go passes the body of requests to the Kubernetes admission endpoint at :9443/admission directly to …","description":"Skipper is an HTTP router and reverse proxy for service composition. Prior to 0.26.22, Handler in dataclients/kubernetes/admission/admission.go passes the body of requests to the Kubernetes admission endpoint at :9443/admission directly to io.ReadAll(r.Body) without a size limit. An attacker with in-cluster network access and a valid Kubernetes client certificate can send a very large body that causes unbounded memory allocation and an out-of-memory termination of the Skipper process. The disruption is limited to Ingress and RouteGroup admission rather than pod creation or unrelated admission controllers, and Kubernetes normally restarts the process. This issue is fixed in version 0.26.22.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","score":4.3,"severity":null}],"references":["https://github.com/zalando/skipper/security/advisories/GHSA-cwxq-rc9x-2jvv","https://github.com/zalando/skipper/pull/4053","https://github.com/zalando/skipper/commit/c3d156c6caaefecc9a46774c0f9c3c70b97160b4","https://github.com/zalando/skipper/releases/tag/v0.26.22"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-78062","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Sep 14, 2026, 8:04:06 PM","dateUpdated":"Sep 16, 2026, 4:19:12 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. 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Prior to 0.26.22, Handler in dataclients/kubernetes/admission/admission.go passes the body of requests to the Kubernetes admission endpoint at :9443/admission directly to io.ReadAll(r.Body) without a size limit. An attacker with in-cluster network access and a valid Kubernetes client certificate can send a very large body that causes unbounded memory allocation and an out-of-memory termination of the Skipper process. The disruption is limited to Ingress and RouteGroup admission rather than pod creation or unrelated admission controllers, and Kubernetes normally restarts the process. This issue is fixed in version 0.26.22.","state":0,"publishedAt":"2026-09-14T20:16:45.843+00:00","modifiedAt":"2026-09-16T17:17:20.6+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","score":4.3,"severity":"MEDIUM"}],"references":["https://github.com/zalando/skipper/commit/c3d156c6caaefecc9a46774c0f9c3c70b97160b4","https://github.com/zalando/skipper/pull/4053","https://github.com/zalando/skipper/releases/tag/v0.26.22","https://github.com/zalando/skipper/security/advisories/GHSA-cwxq-rc9x-2jvv"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-54247","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-770"],"productCriteria":[],"sourceDates":{"published":"2026-09-14T20:16:45.843","lastModified":"2026-09-16T17:17:20.600"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-54247","identifiers":["CVE-2026-54247"]},"retained":false,"historicalAffected":[]},{"revision":"408289ed365048e2a68acf556ab375b8","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-cwxq-rc9x-2jvv","aliases":["CVE-2026-54247","GO-2026-6015"],"title":"Skipper: Unbounded Request Body Read in Admission Webhook Causes Memory Exhaustion DoS","description":"## Summary\n\nThe Kubernetes admission webhook handler reads the entire request body using `io.ReadAll(r.Body)` without any size limit. Any client that can reach the webhook port within the cluster can send a multi-GB payload, causing the skipper process to exhaust memory and be OOM-killed. This disrupts all Kubernetes admission control, potentially blocking all pod creation and updates.\n\n## Vulnerable Code\n\n```go\n// dataclients/kubernetes/admission/admission.go:76\nbody, err := io.ReadAll(r.Body)  // <-- NO SIZE LIMIT\nif err != nil {\n    log.Errorf(\"Failed to read request: %v\", err)\n    w.WriteHeader(http.StatusInternalServerError)\n    invalidRequests.WithLabelValues(admitterName).Inc()\n    return\n}\n\nvar review admissionReview\nerr = json.Unmarshal(body, &review)\n```\n\nFor comparison, the OPA filter has a body size limit:\n\n```go\n// filters/openpolicyagent/openpolicyagent.go:68-70\nconst DefaultMaxRequestBodySize = 1 << 20 // 1MB\n\n// OPA uses a bufferedBodyReader with size limits\n```\n\n## Attack Path\n\n1. Attacker identifies the admission webhook endpoint (default: `:9443/admission` or configured path)\n2. Attacker sends: `POST /admission HTTP/1.1, Content-Type: application/json` with a multi-GB request body\n3. `io.ReadAll(r.Body)` allocates unbounded memory for the entire body\n4. Skipper process is OOM-killed by the Kubernetes kubelet\n\n## Permission Boundary Analysis\n\n- **Attacker**: Any client with network access to the admission webhook port within the Kubernetes cluster\n- **Boundary crossed**: Memory safety — unbounded allocation from attacker-controlled input\n- **Preconditions**: Admission webhook endpoint must be network-reachable (default Kubernetes deployment exposes it within cluster network)\n- **Comparison**: OPA filter has `DefaultMaxRequestBodySize` (1MB) and semaphore-based memory limit; admission handler has neither\n\n## Evidence\n\n| File | Lines | Description |\n|------|-------|-------------|\n| `dataclients/kubernetes/admission/admission.go` | 76 | `io.ReadAll(r.Body)` without size limit |\n| `filters/openpolicyagent/openpolicyagent.go` | 68-70 | OPA filter has `DefaultMaxRequestBodySize` = 1MB |\n| `filters/openpolicyagent/openpolicyagent.go` | 1333-1336 | OPA uses `bufferedBodyReader` with size limits |\n\n## Tests\n\n- `dataclients/kubernetes/admission/admission_test.go` exists but **does not test body size limits**\n\n## Impact\n\nThe admission webhook handler reads the entire request body using io.ReadAll(r.Body) without a size limit. An attacker with in-cluster network access and a valid Kubernetes client certificate can send a multi-GB payload to the webhook endpoint, causing the skipper process to exhaust memory and be OOM-killed. This disrupts admission control for Ingress and RouteGroup resources until the process is automatically restarted by the kubelet.\n\nScope of impact: Ingress and RouteGroup admission only — not pod creation or other admission controllers.\n\nRecovery: Kubernetes automatically restarts the OOM-killed process, limiting downtime.\n\nPrerequisites: (1) In-cluster network access to the webhook port, (2) valid Kubernetes client certificate.\n\n## Mitigation\n\n1. Add `http.MaxBytesReader` or equivalent body size limit before `io.ReadAll`\n2. Follow the OPA filter pattern: define `DefaultMaxRequestBodySize` and use a buffered reader with size limits\n3. Add a configurable `--admission-max-body-size` flag","state":0,"publishedAt":"2026-07-17T18:14:08+00:00","modifiedAt":"2026-07-22T21:11:38.8151256+00:00","affected":[{"ecosystem":"Go","name":"github.com/zalando/skipper","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.26.22"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/zalando/skipper/security/advisories/GHSA-cwxq-rc9x-2jvv","https://github.com/zalando/skipper","https://github.com/zalando/skipper/releases/tag/v0.26.22"],"sourceUrl":"https://github.com/advisories/GHSA-cwxq-rc9x-2jvv","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-cwxq-rc9x-2jvv","identifiers":["GHSA-cwxq-rc9x-2jvv","CVE-2026-54247","GO-2026-6015"]},"retained":false,"historicalAffected":[]},{"revision":"79b13aee4f6c421f945cdde6a2c0a97a","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-6015","aliases":["CVE-2026-54247","GHSA-cwxq-rc9x-2jvv"],"title":"Skipper: Unbounded Request Body Read in Admission Webhook Causes Memory Exhaustion DoS in github.com/zalando/skipper","description":"Skipper: Unbounded Request Body Read in Admission Webhook Causes Memory Exhaustion DoS in github.com/zalando/skipper","state":0,"publishedAt":"2026-07-22T20:36:35+00:00","modifiedAt":"2026-07-22T21:00:25.574217+00:00","affected":[{"ecosystem":"Go","name":"github.com/zalando/skipper","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.26.22"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/zalando/skipper/security/advisories/GHSA-cwxq-rc9x-2jvv","https://github.com/zalando/skipper/releases/tag/v0.26.22"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-6015","license":"OSV · upstream source license applies","key":"osv:GO-2026-6015","identifiers":["GO-2026-6015","CVE-2026-54247","GHSA-cwxq-rc9x-2jvv"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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