Security readout for executives and security teams
Plain-English summary
A malformed Argo Workflows pod annotation can crash the workflow controller. If the poisoned pod remains, the controller may repeatedly crash after restart, stopping workflow processing for the cluster until remediation is performed.
Executive priority
Treat as a high-priority reliability fix for Kubernetes workflow platforms. It can stop all workflow processing, affecting CI, data processing, automation, or ML pipelines using Argo Workflows.
Technical view
Affected Argo Workflows versions have unchecked array indexing in podGCFromPod() while parsing workflows.argoproj.io/pod-gc-strategy. The panic occurs in an informer goroutine outside the controller recover scope, causing a process crash and persistent crash loop.
Likely exposure
Exposure is limited to Kubernetes environments running Argo Workflows 3.6.5-3.6.19, 3.7.0-3.7.13, or 4.0.0-4.0.4. Risk is higher where users or service accounts can create workflow pods or influence pod annotations.
Exploitation context
The provided sources do not show KEV listing or active exploitation. The vulnerability requires low privileges according to CVSS, and impact is availability: crashing the controller and halting workflow processing.
Researcher notes
Evidence supports a controller-wide denial of service through malformed annotation parsing. The bug is CWE-1285 and CWE-129. Sources identify fixed versions but do not provide public exploitation evidence.
Mitigation direction
- Upgrade Argo Workflows to 4.0.5 or 3.7.14, matching your release line.
- For 3.6.x deployments, check vendor guidance; no 3.6 fixed version is named in the bundle.
- Remove any existing poisoned workflow pod causing controller crash loops.
- Restrict who can create workflow pods or modify Argo workflow pod annotations.
Validation and detection
- Inventory Argo Workflows controller versions across all Kubernetes clusters.
- Confirm no deployment runs 3.6.5-3.6.19, 3.7.0-3.7.13, or 4.0.0-4.0.4.
- Review controller logs for repeated panics or crash loops tied to pod GC annotation parsing.
- Inspect existing workflow pods for unexpected workflows.argoproj.io/pod-gc-strategy annotation values.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-1285: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-129: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-40886 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H3.14GitHub_MCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H3.14redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
7.7HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Base CVSS 3.1 score
7.7HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-04-23T19:01:28.433Z: Reported to Red Hat.
- 2026-04-23T18:12:05.782Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/argoproj/argo-workflows/security/advisories/GHSA-5jv8-h7qh-rf5pCVE reference, GitHub_M · x_refsource_CONFIRM
- https://access.redhat.com/security/cve/CVE-2026-40886CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2461236CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40886.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Validation of Specified Index, Position, or Offset in Input
Improper Validation of Specified Index, Position, or Offset in Input represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Improper Validation of Array Index
Improper Validation of Array Index represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.