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CVE-2026-26287 high CVSS 7.1

Vulnerability in github.com/external-secrets/external-secrets (CVE-2026-26287)

Summary

Vulnerability in github.com/external-secrets/external-secrets (CVE-2026-26287). Confidential information can be exposed externally. Exploitable via webhook. Mitigation: upgrade to 1.3.2 or later.

Original description

The description as published by the source.

Summary

A bug in the webhook generator initialization order incorrectly cleared the label-enforcement flag (EnforceLabels) after it was set, resulting in the provider-side check for external-secrets.io/type=webhook being skipped (and the operation to succeed while it should have failed with secret does not contain needed label 'external-secrets.io/type: webhook'. Update secret label to use it with webhook.

Impact

A user with the permission to create webhook generator can set the webhook generator to a victim' secret (which was not previously labelled for webhook's use), and exfiltrate it to a malicious URL.

Mitigations

Until you upgrade, you can reduce risk by:

  • disabling webhook generators if not needed (or denying generators.external-secrets.io/v1alpha1 Webhook via an admission policy);
  • restricting RBAC: limit who can create generators of kind Webhook;
  • enforcing an admission policy (OPA Gatekeeper / Kyverno) requiring referenced secrets to be labeled external-secrets.io/type=webhook;
  • restricting egress from external-secrets controller pods to an allowlist (kubernetes NetworkPolicy / service mesh egress policy).

References

  • PR #5901 (fix: webhook initialization order)

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-2026-26287 has been found in github.com/external-secrets/external-secrets.
Attackers can target a specific entry point like webhook over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: upgrade github.com/external-secrets/external-secrets to 1.3.2 or later.
If unsure, ask your IT team or search "github.com/external-secrets/external-secrets CVE-2026-26287" on the vendor's site.

CVE-2026-26287 (github.com/external-secrets/external-secrets) — CWE-696 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: webhook / EnforceLabels / Webhook / NetworkPolicy
Patched: 1.3.2 — 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.

❓ What is the problem

A vulnerability (CWE-696) exists in github.com/external-secrets/external-secrets. Attackers reach the vulnerable code path via webhook.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/external-secrets/external-secrets. Attack surface: webhook / EnforceLabels / Webhook / NetworkPolicy.

🔥 Severity

Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.

🔧 How to fix

Update to 1.3.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/external-secrets/external-secrets' . 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

  1. 1
    Identify exposure identify 
    grep -r 'github.com/external-secrets/external-secrets' . | 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 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade github.com/external-secrets/external-secrets to 1.3.2

    ステージング環境で 1.3.2 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。

  3. 3
    Post-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

go github.com/external-secrets/external-secrets
[{"type":"SEMVER","events":[{"introduced":"0.10.0"},{"fixed":"1.3.2"}]}]

References

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