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GHSA-cvw6-gfvv-953q

HighCVSS 8.5 / 10
Published Jun 30, 2026·Last modified Jun 30, 2026
Affected Components(0)

No affected components available

Description

Summary

The Fission Function admission webhook (pkg/webhook/function.go) validated that spec.secrets[].namespace and spec.configmaps[].namespace equalled the function's own namespace but performed no equivalent check on spec.environment.namespace.

Details

An attacker with permission to create Functions in their own namespace could set spec.environment.namespace to any other tenant's namespace. poolmgr and newdeploy would then look up and use the victim's Environment CRD when scheduling function pods, so the attacker's function executed inside the victim's container image.

This is useful both for code and credential theft — the victim's runtime image may contain hardcoded secrets — and for confused-deputy attacks where the victim's runtime image is a privileged sidecar.

Impact

A tenant with functions.fission.io/create could run their own function code inside another tenant's container image, breaking the namespace trust boundary that the Function specification implies.

Fix

Fixed in #3389 and released in v1.24.0.

  • Admission webhook (pkg/webhook/function.go::Validate) rejects Function.spec.environment.namespace != metadata.namespace. An empty namespace remains accepted (the CLI defaults it to the function's namespace).
  • Controller belt-and-braces: the same check runs before the cross-namespace Environments(...).Get in poolmgr getFunctionEnv and newdeploy fnCreate / RefreshFuncPods, covering webhook-bypass clusters (failurePolicy=Ignore) and stale Function objects from upgrade-before-restart windows.

Behavioural change

Functions that explicitly set spec.environment.namespace to a different namespace are now rejected at admission. Empty-string remains accepted.

Risk Scores
Base Score
8.5

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a high impact on the confidentiality of the information. There is a low impact on the integrity of the data.

Threat Intelligence
7.8

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.24%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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High severity
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