Fission builder accepts arbitrary buildcmd strings from Environment.spec.builder.command, allowing the builder pod to invoke arbitrary executables

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-46618: 0.36% estimated exploitation activity in the next 30 days; percentile 30.30 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Before the round-1 security sweep, pkg/builder/builder.go passed Environment.spec.builder.command directly into exec.Command(...) after a strings.Fields split, with no validation of the executable path or its arguments. A user who could create or update Environment CRDs in a namespace observed by the buildermgr could thereby point the builder pod at any executable inside the builder image (e.g. /bin/sh -c '...') and execute arbitrary code in the builder pod context. Affected component - pkg/builder/builder.go:254 — call site (exec.Command(buildCmd, buildArgs...)). - pkg/builder/builder.go:106 — input source: buildCmd, buildArgs = strings.Fields(req.BuildCommand)[0], strings.Fields(req.BuildCommand)[1:]. Impact A subject with create / update privilege on Environment objects could: 1. Cause the builder pod for any package using that environment to execute arbitrary code. 2. Read whatever files the builder pod has access to inside its /packages shared volume (deployment archive…

Published by the source

21 May 2026, 20:17 UTC

Last modified by the source

10 Jun 2026, 18:42 UTC

Source last checked

26 Oct 2026, 15:23 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-7pjr-qpvh-m339

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# Patch Next advisory brief: CVE-2026-46618

Advisory: Fission builder accepts arbitrary buildcmd strings from Environment.spec.builder.command, allowing the builder pod to invoke arbitrary executables
IDs: CVE-2026-46618, GHSA-7pjr-qpvh-m339
Record: https://patchnext.com/advisories/cve-2026-46618 (revision 1, source checked 26 Oct 2026, 15:23 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/fission/fission 1.23.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/fission/fission: affected <= 1.22.0; fixed in 1.23.0

## Suggested inspection (read-only)
- Go github.com/fission/fission: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/fission/fission.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7pjr-qpvh-m339 (GitHub-reviewed advisory GHSA-7pjr-qpvh-m339 lists affected ranges: Go github.com/fission/fission >=0 <=1.22.0)

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