{"id":"CVE-2026-49823","aliases":["GHSA-3r8v-2xmj-5c39","GO-2026-5846"],"url":"https://o3.security/vulnerability/CVE-2026-49823","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.","published":"2026-06-10T17:23:23.682Z","modified":"2026-08-12T03:51:33.652635455Z","cvss":{"score":7.7,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},"epss":{"score":0.00265,"percentile":0.18634,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/fission/fission","fixedVersion":"1.24.0"}],"fix":{"url":"https://github.com/fission/fission/pull/3389","label":"fission/fission#3389"},"references":[{"type":"WEB","url":"https://github.com/fission/fission/releases/tag/v1.24.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49823.json"},{"type":"ADVISORY","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":"FIX","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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:33.652635455Z"}}