CVE-2026-50564: Fission privilege escalation via PodSpec injection in Environment CRD

CVE-2026-50564 · Severity: critical · CVSS 9.9 · Published 2026-06-10

Fission is a framework for serverless functions on Kubernetes. A security flaw allowed users with basic permissions to create malicious configurations that bypass standard security boundaries. An attacker could use this to escape their isolated environment, gain full control over the underlying server (node), and potentially compromise the entire data center or cloud cluster.

Technologies: Fission, github.com/fission/fission (Go). Vendors: Fission, Go.

Quick answers

Is CVE-2026-50564 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-50564 being exploited in the wild.
How severe is CVE-2026-50564?
Critical severity, with a CVSS score of 9.9, published 10 June 2026.
Which products and versions are affected?
Fission <= 1.23.0; github.com/fission/fission (Go) <= 1.23.0, SEMVER:introduced=0,fixed=1.24.0.
Is there a fix for CVE-2026-50564?
Yes. github.com/fission/fission (Go): upgrade to 1.24.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-50564 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-50564?
Check whether you run Fission or github.com/fission/fission (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/fission/fission (Go): upgrade to 1.24.0 or later
    go get github.com/fission/fission@v1.24.0

Technical details

The Fission Environment Custom Resource Definition (CRD) improperly handled 'spec.runtime.podSpec' and 'spec.builder.podSpec' fields, merging them into Kubernetes pod specs without validation or filtering. An attacker with 'create' or 'update' RBAC permissions on 'environments.fission.io' could inject dangerous fields such as 'hostNetwork', 'hostPID', 'hostIPC', and 'privileged: true'. Because Fission-managed namespaces lacked Pod Security Admission enforcement, these pods were successfully scheduled. This allows an attacker to use 'nsenter' to escape to the host, access cloud-metadata credentials, and achieve full node compromise. The fix in v1.24.0 introduces an admission denylist and sanitization at the merge layer.

Affected products

  • fission fission <= 1.23.0

Identifiers

  • CVE-2026-50564
  • GHSA-gx55-f84r-v3r7
  • GO-2026-5855

Timeline

  • 2026-05-26: disclosed
  • 2026-06-10: advisory: NVD publication
  • 2026-06-30: patched: GitHub Advisory published/updated with fix details

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.