CVE-2026-49821 Fission: Cross-namespace Environment reference in Package allows build-time command execution and SA token exfiltration
Attackers can execute commands and steal service account tokens by referencing environments across namespaces in Fission packages.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-49821?
CVE-2026-49821 is a high-severity missing authorization vulnerability in fission, published on 10 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Fission is an open-source, Kubernetes-native serverless framework that simplifies the deployment of functions and applications on Kubernetes. Prior to version 1.24.0, Fission's buildermgr controller processed Package CRDs without verifying that Package.spec.environment.namespace matched Package.metadata.namespace. This issue has been patched in version 1.24.0.
Which versions are affected by CVE-2026-49821?
3 open source packages ship an affected version, including github.com/fission/fission.
| Package | Affected | Fixed in |
|---|---|---|
github.com/fission/fission Go | All versions | 1.24.0 |
github.com/fission/fission Go | All versions | 1.24.0 |
github.com/fission/fission Go | All versions | 1.24.0 |
How do I fix CVE-2026-49821?
Upgrade github.com/fission/fission to 1.24.0 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-49821 being exploited?
There is no known exploitation of CVE-2026-49821 in the wild and no public exploit code.
Sources
Also known as GHSA-vjhc-cf4p-72q4, GO-2026-5859.