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

Source: https://junglewise.ai/threats/cve-2026-50564-fission-privilege-escalation-via-podspec-injection-in-environment  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-10. Updated: 2026-06-30  
License: CC BY 4.0 with a link back

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](https://junglewise.ai/threats/technologies/fission), [github.com/fission/fission (Go)](https://junglewise.ai/threats/technologies/github-com-fission-fission). Vendors: [Fission](https://junglewise.ai/threats/vendors/fission), [Go](https://junglewise.ai/threats/vendors/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

  ```sh
  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

- [https://api.github.com/users/0xVijay](https://api.github.com/users/0xVijay)
- [https://github.com/0xVijay](https://github.com/0xVijay)
- [https://api.github.com/users/0xVijay/gists%7B/gist_id%7D](https://api.github.com/users/0xVijay/gists%7B/gist_id%7D)
- [https://api.github.com/users/0xVijay/repos](https://api.github.com/users/0xVijay/repos)
- [https://avatars.githubusercontent.com/u/53905346?v=4](https://avatars.githubusercontent.com/u/53905346?v=4)
- [https://api.github.com/users/0xVijay/events%7B/privacy%7D](https://api.github.com/users/0xVijay/events%7B/privacy%7D)

## Related threats

- [GO-2026-5849 - Fission: MessageQueueTrigger scaler manager materializes Secret values into Deployment envvars and accepts arbitrary user PodSpec in github.](https://junglewise.ai/threats/go-2026-5849-fission-messagequeuetrigger-scaler-manager-materializes-509f5f41)
- [Fission privilege escalation in MessageQueueTrigger scaler manager](https://junglewise.ai/threats/fission-privilege-escalation-in-messagequeuetrigger-scaler-manager-7fe266a4)
- [Fission incomplete capability denylist in Environment and Function CRDs](https://junglewise.ai/threats/cve-2026-50570-fission-incomplete-capability-denylist-in-environment-and)
- [Fission HTTPTrigger improper input validation in RelativeURL and Prefix](https://junglewise.ai/threats/cve-2026-50569-fission-httptrigger-improper-input-validation-in-relativeurl-and)
- [Fission path traversal in SanitizeFilePath utility](https://junglewise.ai/threats/cve-2026-50568-fission-path-traversal-in-sanitizefilepath-utility)