GHSA-p4gq-3vxj-f4jqPublished

Argo Workflows: SSO RBAC Delegation Nil Pointer Dereference DoS (gatekeeper.go)

Exploitation and risk

CISA KEV lists vulnerabilities known to be exploited. FIRST EPSS estimates the likelihood of exploitation in the next 30 days. An unavailable score does not mean zero risk.

Which CVEs have scores here?

This view includes predictions for CVE identifiers explicitly listed in public NuGet advisories. Microsoft release pages have their own prediction coverage. Check source status for the scope and latest checks.

No exploitation or prediction data is available here for these CVEs. This does not mean they are safe or unlikely to be exploited.

cve-program · CVE-2026-42183

Published

Argo Workflows is an open source container-native workflow engine for orchestrating parallel jobs on Kubernetes. From version 4.0.0 to before version 4.0.5, a nil pointer dereference in server/auth/gatekeeper.go rbacAuthorization() causes a panic (denial of service) for SSO users whose claims match a namespace-level RBAC rule but not an SSO-namespace rule, when SSO_DELEGATE_RBAC_TO_NAMESPACE=true. This issue has been patched in version 4.0.5.

Source published: 9 May 2026 03:44:10 UTC
Source modified: 13 May 2026 17:46:04 UTC
Saved here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · 2.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

euvd · EUVD-2026-28891

Published

Additional publisher context

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: May 9, 2026, 3:44:10 AM

dateUpdated: May 13, 2026, 5:46:04 PM

Source published: May 9, 2026, 3:44:10 AM (timezone not stated)
Source modified: May 13, 2026, 5:46:04 PM (timezone not stated)
Saved here: 13 Nov 2026 12:02:13 UTC
Source terms: ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 4.0 · 2.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

nvd · CVE-2026-42183

Published

Additional publisher context

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-476

Original publisher date fields

published: 2026-05-09T04:16:23.810

lastModified: 2026-07-24T21:10:00.143

1 source CPE criteria · context only

cpe:2.3:a:argoproj:argo_workflows:*:*:*:*:*:go:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 9 May 2026 04:16:23 UTC
Source modified: 24 Jul 2026 21:10:00 UTC
Saved here: 25 Oct 2026 10:17:10 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · [email protected] · Secondary · 2.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv · GHSA-p4gq-3vxj-f4jq

Published

### Summary A nil pointer dereference in `server/auth/gatekeeper.go` `rbacAuthorization()` causes a panic (denial of service) for SSO users whose claims match a namespace-level RBAC rule but not an SSO-namespace rule, when `SSO_DELEGATE_RBAC_TO_NAMESPACE=true`. ### Details When `getServiceAccount(claims, ssoNamespace)` returns nil (no matching rule), the error is suppressed and `loginAccount` remains nil. If RBAC delegation finds a matching `namespaceAccount`, line 304 calls `precedence(loginAccount)` which unconditionally accesses `serviceAccount.Annotations` — nil pointer dereference. **Affected code (v4.0.4):** ```go // gatekeeper.go:304 } else if precedence(namespaceAccount) > precedence(loginAccount) { // loginAccount is nil here -> precedence(nil) -> PANIC // gatekeeper.go:232-234 func precedence(serviceAccount *corev1.ServiceAccount) int { i, _ := strconv.Atoi(serviceAccount.Annotations[common.AnnotationKeyRBACRulePrecedence]) return i } ``` ### PoC **Live-tested 2026-04-17:** kind cluster, Argo Workflows v4.0.4, Dex v2.43.1 OIDC provider. 1. Deploy Argo Workflows with `--auth-mode=sso --auth-mode=client`, SSO pointing to Dex, RBAC enabled. 2. Set `SSO_DELEGATE_RBAC_TO_NAMESPACE=true` on the argo-server deployment. 3. Create an RBAC ServiceAccount with `workflows.argoproj.io/rbac-rule: "true"` annotation in a target namespace (e.g., `target-ns`). 4. Do **not** create a matching RBAC rule in the SSO namespace (`argo`). 5. Authenticate via the Dex SSO flow. 6. Request `GET /api/v1/workflows/target-ns` with the SSO session cookie. 7. Server returns HTTP 500: `{"code":13,"message":"runtime error: invalid memory address or nil pointer dereference"}` 8. Server logs: `Recovered from panic` with stack trace at `gatekeeper.go:233` (`precedence()`) called from `gatekeeper.go:304`. Every subsequent API request from affected SSO users triggers the same panic. ### Impact Permanent denial of service for any SSO user whose claims don't match SSO-namespace RBAC but do match a target namespace rule. Realistic in multi-tenant deployments with per-namespace RBAC. The gRPC recovery interceptor catches the panic so the server process survives, but the affected user gets HTTP 500 on every request. ### Suggested Fix Add nil check: `if loginAccount == nil || precedence(namespaceAccount) > precedence(loginAccount)` ### AI Disclosure This advisory was prepared with AI assistance (Claude Code, Anthropic).

Source published: 4 May 2026 20:01:13 UTC
Source modified: 10 Sep 2026 03:50:47 UTC
Saved here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Publisher rating · LOW

osv · GO-2026-5527

Published

Argo Affected by SSO RBAC Delegation Nil Pointer Dereference DoS (gatekeeper.go) in github.com/argoproj/argo-workflows

Source published: 25 Jun 2026 22:34:34 UTC
Source modified: 2 Jul 2026 14:44:23 UTC
Saved here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · OSV · upstream source license applies. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.