CVE-2026-40886

Argo Workflows: Unchecked annotation parsing in pod informer crashes Argo Workflows controller

HIGH
7.7
CVSS Score
Published: April 23, 2026 at 06:12 PM UTC
Updated: October 26, 2026 at 10:10 PM UTC
1 product affected across 1 vendorArgo Workflows

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Severity
HIGH7.7
Exploit prediction
EPSS 0.4%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

3.6.5 ≤ v ≤ 3.6.193.7.0 ≤ v < 3.7.144.0.0 ≤ v < 4.0.5
Affected range stops below 3.7.14, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.0.5, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/argoproj/argo-workflows/security/advisories/GHSA-5jv8-h7qh-rf5p
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-40886
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://bugzilla.redhat.com/show_bug.cgi?id=2461236

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.7HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-129CWE-1285

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