Vulnerability in github.com/external-secrets/external-secrets/apis (CVE-2026-42876)
Summary
Vulnerability in github.com/external-secrets/external-secrets/apis (CVE-2026-42876). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 2.4.1 or later.
Original description
The description as published by the source.
ExternalSecrets allows users to craft Service Account tokens for misconfigured Service Accounts in namespaces the users have access to.
Impact
A user who only has permission to create ExternalSecret resources can cause the operator to create a Secret that Kubernetes will automatically populate with a long-lived token for the sepcified service account. This effectively allows the user to impersonate any service account in the namespace without needing direct create permissions on TokenRequest or Secrets of that type.
The problem is mitigated in severity by the fact that the user must have pre-existing permissions already at almost the same level as the escalation later gives. The attacker cannot use this method to gain access to more information without other things also being misconfigured in the ESO installation.
Patches
Disallow this combination including the bootstrap token secret type.
Workarounds
- Add admission control logic to prevent the use of Templates targeting undesired Types
- Remove Service Account Token generation via kube-controller-manager flags
- Restrict User RBAC on production clusters and sensitive namespaces
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-42876 has been found in github.com/external-secrets/external-secrets/apis.
Risk of unauthorized operations or information disclosure. CVSS score: 4.9/10.
What to do: upgrade github.com/external-secrets/external-secrets/apis to 2.4.1 or later.
If unsure, ask your IT team or search "github.com/external-secrets/external-secrets/apis CVE-2026-42876" on the vendor's site.
CVE-2026-42876 (github.com/external-secrets/external-secrets/apis) — CWE-285 / CVSS v3 4.9
Attack vector: remote (network-reachable) / no user interaction
Patched: 2.4.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-285) exists in github.com/external-secrets/external-secrets/apis.
Check the vendor advisory for the affected versions of github.com/external-secrets/external-secrets/apis.
Severity: Medium (CVSS 4.9/10). Risk of unauthorized operations or information disclosure.
Update to 2.4.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/external-secrets/external-secrets/apis' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/external-secrets/external-secrets/apis' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/external-secrets/external-secrets/apisを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade github.com/external-secrets/external-secrets/apis to 2.4.1ステージング環境で 2.4.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com