CVE-2026-46618: Fission OS command injection in builder component

CVE-2026-46618 · Severity: medium · CVSS 4 · Published 2026-06-10

Fission is a framework used to run serverless functions on Kubernetes. A security flaw in the builder component allowed users with permission to create or update environment configurations to execute unauthorized commands within the system's build environment. This could allow an attacker to view or modify application code packages before they are deployed, potentially compromising the integrity of functions running on the platform.

Technologies: Fission, github.com/fission/fission (Go). Vendors: Fission, Go.

Quick answers

Is CVE-2026-46618 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-46618 being exploited in the wild.
How severe is CVE-2026-46618?
Medium severity, with a CVSS score of 4, published 10 June 2026.
Which products and versions are affected?
Fission <= 1.22.0, <= v1.22.0; github.com/fission/fission (Go) <= 1.22.0, SEMVER:introduced=0,fixed=1.23.0.
Is there a fix for CVE-2026-46618?
Yes. github.com/fission/fission (Go): upgrade to 1.23.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-46618 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-46618?
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 1.23.0 or later
    go get github.com/fission/fission@v1.23.0

Technical details

A command injection vulnerability existed in `pkg/builder/builder.go` where `Environment.spec.builder.command` was passed directly to `exec.Command()` after a simple `strings.Fields` split without validation. An attacker with permissions to create or update Environment Custom Resource Definitions (CRDs) could specify arbitrary executables (e.g., `/bin/sh`) and arguments. This allows for arbitrary code execution within the builder pod's context, enabling the attacker to read or modify package deployment archives in the shared `/packages` volume. The issue was addressed in version 1.23.0 by implementing `Builder.resolveBuildCommand` to validate executable paths and reject relative paths or whitespace metacharacters.

Affected products

  • Fission Fission <= v1.22.0

Identifiers

  • CVE-2026-46618
  • GHSA-7pjr-qpvh-m339
  • GO-2026-5230

Timeline

  • 2026-05-07: patched: Security fixes merged in PR #3364
  • 2026-05-15: advisory: GitHub Security Advisory GHSA-7pjr-qpvh-m339 published
  • 2026-06-10: disclosed: CVE-2026-46618 published to NVD

References

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