CVE-2026-50569: Fission HTTPTrigger Admission Omits RelativeURL / Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-vchh-r53j-8mpw",
  "modified" : "2026-07-28T20:16:00Z",
  "published" : "2026-07-28T20:16:00Z",
  "aliases" : [ "CVE-2026-50569" ],
  "summary" : "Fission: HTTPTrigger admission omits RelativeURL / Prefix validation; kubectl apply bypasses CLI checks",
  "details" : "`HTTPTriggerSpec.Validate()` validated `Methods`, `FunctionReference`, `Host`, `IngressConfig`, and `CorsConfig`, but silently skipped `RelativeURL` and `Prefix`. Those two fields were validated at the CLI level only\n(`pkg/fission-cli/cmd/httptrigger/create.go:83`). The post-CRD-modernization webhook for HTTPTrigger was retired in favor of API-server CEL — and CEL had no rules on those fields either — so an HTTPTrigger created via `kubectl apply` or\na direct Kubernetes REST API call bypassed every URL-level check.\n\nA tenant with HTTPTrigger create permission could therefore create triggers whose `RelativeURL` or `Prefix`:\n\n- was empty (with both fields unset, the trigger has no URL),\n- did not start with `/`,\n- was exactly `/` (claiming the entire router root),\n- contained `..` traversal segments (e.g. `/api/../admin`),\n- collided with router-owned routes: `/router-healthz`, `/readyz`, `/_version`, `/auth/login`,\n- collided with the router-internal function prefix `/fission-function/<ns>/<name>`.\n\n### Affected\n\n- Project: `github.com/fission/fission`\n- Versions: all versions through v1.24.0\n- Audited commit: `647c141`\n- Component: `pkg/apis/core/v1/validation.go:HTTPTriggerSpec.Validate` (and the missing CEL on `HTTPTriggerSpec`)\n- Configuration: default\n\nFix section (paste into the Fix / Patches field)\n\nFixed in [v1.25.0](https://github.com/fission/fission/releases/tag/v1.25.0) by:\n\n- [PR #3464](https://github.com/fission/fission/pull/3464) (commit [`0deed6bf`](https://github.com/fission/fission/commit/0deed6bf2af2a0c0c6094b25e1a0afad36773e3b)) — enforce the path-safety invariants at both admission layers so the API\nserver's CEL evaluation and the Go-side `HTTPTriggerSpec.Validate()` agree:\n  - Three `+kubebuilder:validation:XValidation` rules on `HTTPTriggerSpec` (the API server's CEL admission gate, regenerated into `crds/v1/fission.io_httptriggers.yaml`):\n    - at least one of `relativeurl` or `prefix` must be non-empty;\n    - `relativeurl`, when set, must start with `/`, must not be `/`, must contain no `..` segment, must not be in the reserved exact-path set, and must not start with `/fission-function/`;\n    - `prefix`, when set, the same rules guarded by `has(self.prefix)`.\n  - `validateTriggerPath` helper in `pkg/apis/core/v1/validation.go`, invoked from `HTTPTriggerSpec.Validate()`, mirrors the CEL rules so the CLI's early rejection and the router reconciler's status-Condition path match what the API\nserver admits.\n\nRegression coverage: a new `TestHTTPTriggerSpecValidate_Path` table in `pkg/apis/core/v1/validation_validators_test.go` exercises every PoC case from the advisory plus literal `..`-prefixed-segment positives that must remain allowed.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/fission/fission"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.25.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.24.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/security/advisories/GHSA-vchh-r53j-8mpw"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-50569"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/pull/3464"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/commit/0deed6bf3f26bc0f10e9130cd0d479b0b9f5f609"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fission/fission"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fission/fission/releases/tag/v1.25.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-28T20:16:00Z",
    "nvd_published_at" : "2026-06-10T18:17:13Z"
  }
}