Fission: Cross-namespace event leakage via KubernetesWatchTrigger allows persistent tenant surveillance

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.7 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

EPSS

• CVE-2026-49822: 0.23% estimated exploitation activity in the next 30 days; percentile 14.02 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A low-privilege developer who could create a KubernetesWatchTrigger (KWT) in their own namespace was able to establish a persistent surveillance channel over any other namespace. Details Two independent flaws compounded: 1. pkg/kubewatcher/kubewatcher.go::createKubernetesWatch used w.Spec.Namespace (user-controlled) directly as the Watch target without checking it against w.Namespace (the KWT's own namespace). kubewatcher established the Watch using its cluster-scoped service account and serialized every Pod/Service/Job change event as full JSON over HTTP POST to the attacker's function. 2. The validating webhook (pkg/webhook/kuberneteswatchtrigger.go) registered verbs=create only, so update/patch requests bypassed validation entirely. A separate leak: an empty spec.namespace resolved to all namespaces via the controller's default, letting an attacker omit the field to surveil the entire cluster. Impact A tenant with kuberneteswatchtriggers.fission.io/create could…

Published by the source

30 Jun 2026, 18:16 UTC

Last modified by the source

30 Jun 2026, 18:16 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gc3j-79f2-7vvw

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# Patch Next advisory brief: CVE-2026-49822

Advisory: Fission: Cross-namespace event leakage via KubernetesWatchTrigger allows persistent tenant surveillance
IDs: CVE-2026-49822, GHSA-gc3j-79f2-7vvw
Record: https://patchnext.com/advisories/cve-2026-49822 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/fission/fission 1.24.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/fission/fission: affected <= 1.23.0; fixed in 1.24.0

## Suggested inspection (read-only)
- Go github.com/fission/fission: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/fission/fission.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gc3j-79f2-7vvw (GitHub-reviewed advisory GHSA-gc3j-79f2-7vvw lists affected ranges: Go github.com/fission/fission >=0 <=1.23.0)

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