{"id":"GHSA-3r8v-2xmj-5c39","summary":"Fission: Cross-namespace Package read via unvalidated PackageRef in Function admission webhook","details":"### Summary\n\nA Fission Function spec carries three reference types — Secret, ConfigMap, and Package. The first two were namespace-validated by the admission webhook; `PackageRef.Namespace` was not.\n\n### Details\n\nA tenant with `functions.fission.io/create` in their own namespace could set `spec.package.packageref.namespace` to any other namespace. When the function is invoked, the fetcher sidecar reads the victim Package using the\n`fission-fetcher` service account's namespace-wide `get packages` permission and writes its contents to `/userfunc/deployarchive` inside the attacker's pool pod, exposing the victim's source code and any embedded credentials.\n\nThe `fission-fetcher` SA holds `get packages` in every configured function namespace (granted by `charts/fission-all/templates/_function-access-role.tpl`), so the namespace check was the only barrier between the attacker and any\nin-cluster Fission Package.\n\n### Impact\n\nA function author in one namespace could read the deployment archive — and therefore the source code and embedded secrets — of any Package in any other namespace.\n\n### Fix\n\nFixed in [#3389](https://github.com/fission/fission/pull/3389) and released in [v1.24.0](https://github.com/fission/fission/releases/tag/v1.24.0).\n\nThe admission webhook (`pkg/webhook/function.go::Validate`) rejects `Function.spec.package.packageref.namespace != metadata.namespace`. An empty namespace remains accepted (controllers default it to the function's namespace). This\nshipped together with the EnvironmentRef cross-namespace check (GHSA-cvw6-gfvv-953q).\n\n### Behavioural change\n\nFunctions that explicitly set `spec.package.packageref.namespace` to a different namespace are now rejected at admission.","aliases":["CVE-2026-49823","GO-2026-5846"],"modified":"2026-07-07T16:11:42.810618067Z","published":"2026-06-30T18:16:33Z","database_specific":{"cwe_ids":["CWE-284","CWE-863"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-06-30T18:16:33Z","nvd_published_at":"2026-06-10T18:17:10Z"},"references":[{"type":"WEB","url":"https://github.com/fission/fission/security/advisories/GHSA-3r8v-2xmj-5c39"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49823"},{"type":"WEB","url":"https://github.com/fission/fission/pull/3389"},{"type":"WEB","url":"https://github.com/fission/fission/commit/80e7ba55228e1ef426f51353e25d2682ec61de34"},{"type":"PACKAGE","url":"https://github.com/fission/fission"},{"type":"WEB","url":"https://github.com/fission/fission/releases/tag/v1.24.0"}],"affected":[{"package":{"name":"github.com/fission/fission","ecosystem":"Go","purl":"pkg:golang/github.com/fission/fission"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.24.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-3r8v-2xmj-5c39/GHSA-3r8v-2xmj-5c39.json","last_known_affected_version_range":"\u003c= 1.23.0"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"}]}