CVE-2026-40886: argoproj argo-workflows · Improper Validation of Array Index
Affects argoproj argo-workflowsSource CVE Database V5
Not known to be exploited · CVSS 7.7 High : upgrade to 4.0.5 or 3.7.14 soon.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.0.5, 3.7.14
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade argo-workflows and github.com/argoproj/argo-workflows to 4.0.5 or 3.7.14.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| argoprojargo-workflows | Affected
| Fixed in
|
Gogithub.com/argoproj/argo-workflowspkg:golang/github.com/argoproj/argo-workflowsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in Argo Workflows versions 4.0.5 and 3.7.14. Users should upgrade to these versions or later to remediate the vulnerability. Until upgrading, manual deletion of any pods with malformed workflows.argoproj.io/pod-gc-strategy annotations can temporarily mitigate the crash loop. Patch status is confirmed by the vendor advisory from Red Hat.
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.
References
- github.com/argoproj/argo-workflows/security/advisories/GHSA-5jv8-h7qh-rf5p (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-40886 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2461236 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40886.json (opens in a new tab)