Summary
Fission: Cross-namespace Environment reference via unvalidated EnvironmentRef in Function admission webhook
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 onspec.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.
Behavioural change
Functions that explicitly set spec.environment.namespace to a different namespace are now rejected at admission. Empty-string remains accepted.
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.
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2026-49824 has a CVSS score of 8.5 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.24.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
Fixed in #3389 and released in v1.24.0.
- Admission webhook (
pkg/webhook/function.go::Validate) rejectsFunction.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(...).Getin poolmgrgetFunctionEnvand newdeployfnCreate/RefreshFuncPods, covering webhook-bypass clusters (failurePolicy=Ignore)
and stale Function objects from upgrade-before-restart windows.
Frequently Asked Questions
- What is CVE-2026-49824? CVE-2026-49824 is a high-severity incorrect authorization vulnerability in github.com/fission/fission (go), affecting versions <= 1.23.0. It is fixed in 1.24.0. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2026-49824? CVE-2026-49824 has a CVSS score of 8.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/fission/fission are affected by CVE-2026-49824? github.com/fission/fission (go) versions <= 1.23.0 is affected.
- Is there a fix for CVE-2026-49824? Yes. CVE-2026-49824 is fixed in 1.24.0. Upgrade to this version or later.
- Is CVE-2026-49824 exploitable, and should I be worried? Whether CVE-2026-49824 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-49824 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-49824? Upgrade
github.com/fission/fissionto 1.24.0 or later.