CVE-2026-49821 is a high-severity missing authorization vulnerability in github.com/fission/fission (go), affecting versions <= 1.23.0. It is fixed in 1.24.0.
Summary Fission's buildermgr controller processed Package CRDs without verifying that Package.spec.environment.namespace matched Package.metadata.namespace. Details An attacker with packages.fission.io/create in their own namespace could set spec.environment.namespace to any other tenant's namespace. The controller then used its high-privilege service account to fetch the Environment cross-namespace and dispatch the build command into the victim namespace's builder pod. The build command's stdout is written verbatim into Package.status.buildlog. By running malicious code through an npm preinstall lifecycle hook (or any equivalent build step), the attacker could read the victim namespace's fission-builder Bearer token from inside that builder pod and surface it through the build log, then use the leaked token to read every Secret and ConfigMap in the victim namespace. Impact Cross-tenant compromise: a package author in one namespace could execute code inside another tenant's builder pod and exfiltrate that namespace's fission-builder service-account token, giving namespace-wide secret and configmap read in the victim namespace. Fix Fixed in #3379 and released in v1.24.0. Two checks in series: Admission webhook (pkg/webhook/package.go::Validate) rejects Package.spec.environment.namespace != Package.metadata.namespace. An empty namespace is still accepted; the controllers default it to the package's own namespace. Controller belt-and-braces: the same check is repeated in pkg/buildermgr/pkgwatcher.go::build and pkg/buildermgr/common.go::buildPackage before the cross-namespace Environments(...).Get call, so a stale Package CR or a webhook-bypass cluster (failurePolicy=Ignore) cannot exploit the primitive either. Behavioural change Packages that explicitly set spec.environment.namespace to a different namespace are now rejected at admission. Empty-string remains accepted (resolves to the package's own namespace, the same as the prior implicit behaviour).
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
CVE-2026-49821 has a CVSS score of 7.7 (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.
go
github.com/fission/fission (<= 1.23.0)github.com/fission/fission → 1.24.0 (go)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.
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Already deployed Kodem? See CVE-2026-49821 in your environment →Upgrade github.com/fission/fission to 1.24.0 or later to resolve this vulnerability.
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CVE-2026-49821 is a high-severity missing authorization vulnerability in github.com/fission/fission (go), affecting versions <= 1.23.0. It is fixed in 1.24.0. The application does not perform an authorization check before performing a sensitive operation.
CVE-2026-49821 has a CVSS score of 7.7 (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.
github.com/fission/fission (go) versions <= 1.23.0 is affected.
Yes. CVE-2026-49821 is fixed in 1.24.0. Upgrade to this version or later.
Whether CVE-2026-49821 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
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.
Upgrade github.com/fission/fission to 1.24.0 or later.