GHSA-3R8V-2XMJ-5C39
Vulnerability from github – Published: 2026-06-30 18:16 – Updated: 2026-06-30 18:16Summary
A 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.
Details
A 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
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.
The 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
in-cluster Fission Package.
Impact
A 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.
Fix
Fixed in #3389 and released in v1.24.0.
The 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
shipped together with the EnvironmentRef cross-namespace check (GHSA-cvw6-gfvv-953q).
Behavioural change
Functions that explicitly set spec.package.packageref.namespace to a different namespace are now rejected at admission.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.23.0"
},
"package": {
"ecosystem": "Go",
"name": "github.com/fission/fission"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.24.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-49823"
],
"database_specific": {
"cwe_ids": [
"CWE-284",
"CWE-863"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-30T18:16:33Z",
"nvd_published_at": "2026-06-10T18:17:10Z",
"severity": "HIGH"
},
"details": "### Summary\n\nA Fission Function spec carries three reference types \u2014 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\u0027s namespace-wide `get packages` permission and writes its contents to `/userfunc/deployarchive` inside the attacker\u0027s pool pod, exposing the victim\u0027s 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 \u2014 and therefore the source code and embedded secrets \u2014 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\u0027s 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.",
"id": "GHSA-3r8v-2xmj-5c39",
"modified": "2026-06-30T18:16:33Z",
"published": "2026-06-30T18:16:33Z",
"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"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Fission: Cross-namespace Package read via unvalidated PackageRef in Function admission webhook"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.