8.7

CVSS Score

4.0

-

CVSS Score

Basic Information

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CVE-2026-46617

CVE-2026-46617: Fission runtime pods automount the fission-fetcher service-account token into the user function container, granting function code namespace-wide secret / configmap read

Summary

Fission runtime pods were created with ServiceAccountName: fission-fetcher, and the fission-fetcher ServiceAccount was granted namespace-wide get on secrets and configmaps (it needs that to load function code, env vars, and config). The runtime pod's automounted token was reachable from inside the user's function container at /var/run/secrets/kubernetes.io/serviceaccount/token, so user-supplied function code inherited the same Kubernetes API privileges and could read any secret or configmap in the function's namespace — far beyond the Function.spec.secrets allowlist that the function specification suggests.

Affected component

pkg/executor/executortype/poolmgr/gp_deployment.go:154-156 — pool-manager runtime pod ServiceAccountName.
pkg/executor/executortype/newdeploy/newdeploy.go:225-227 — new-deploy runtime pod ServiceAccountName.
pkg/utils/serviceaccount.go:51-64 — fission-fetcher RBAC: namespace-wide get on secrets / configmaps.

Impact

A user able to deploy or update a function in any namespace where Fission runtime pods are scheduled could:

Read every secret in that namespace (TLS keys, OIDC client secrets, database credentials, cloud provider credentials).
Read every configmap in that namespace.
Use those credentials to pivot to other Kubernetes resources or external systems the secrets unlock.

This violates the principle that Function.spec.secrets is the authoritative declaration of which secrets a function can read.

Root cause

The fetcher sidecar legitimately needs the SA token to call the Fission control plane and fetch package archives. Setting on the pod gives every container in the pod (including the user container) the automounted token. Kubernetes does not provide per-container service-account scoping inside a single pod, so the user container has to be moved into a separate identity / token-mount scheme.

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CVE-2026-46617

CVE-2026-46617:

8.7

CVSS Score

4.0

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
github.com/fission/fission	go	<= 1.22.0	1.23.0

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability lies in the Fission runtime pods, which were created with ServiceAccountName: fission-fetcher. This service account had namespace-wide get permissions on secrets and configmaps. The service account token was automounted into the user function container, allowing user-supplied code to inherit these broad permissions and access any secret or configmap in the function's namespace.

The fix involves several changes across multiple files to prevent this token leakage:

Disabling Automount: The AutomountServiceAccountToken is now explicitly set to false at the pod level for both poolmgr and newdeploy executor types. This prevents Kubernetes from automatically mounting the service account token into any container within the pod.
Projected Volume for Fetcher: A projected volume is now used to mount the fission-fetcher service account token only into the fetcher container. This ensures that the fetcher, which legitimately needs to communicate with the Kubernetes API, can do so without exposing the token to the user function container.
Enforcing the Fix: The code was updated to re-apply the AutomountServiceAccountToken: false setting after merging any user-provided PodSpec patches. This prevents a malicious or misconfigured user from re-enabling the token automount.

The vulnerable functions are those responsible for generating the pod specifications for the Fission function runtimes. Specifically, genDeploymentSpec in gp_deployment.go and getDeploymentSpec in newdeploy.go were modified to implement the fix.

Vulnerable functions

github.com/fission/fission/pkg/executor/executortype/poolmgr.(*GenericPool).genDeploymentSpec

pkg/executor/executortype/poolmgr/gp_deployment.go

This function generates the deployment specification for pool-managed functions. Before the patch, it did not disable the automounting of the service account token, allowing the user function container to inherit the `fission-fetcher`'s permissions. The patch adds `AutomountServiceAccountToken: &automountSAToken` (where `automountSAToken` is `false`) and a projected volume for the fetcher, mitigating the vulnerability.

github.com/fission/fission/pkg/executor/executortype/newdeploy.(*NewDeploy).getDeploymentSpec

pkg/executor/executortype/newdeploy/newdeploy.go

This function generates the deployment specification for new-deploy functions. Like `genDeploymentSpec`, it was vulnerable because it allowed the user function container to access the `fission-fetcher` service account token. The patch applies the same mitigation: disabling automount and using a projected volume.

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WAF Rule

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Reasoning

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