Information Disclosure in cilium (CVE-2026-41520)
Summary
Vulnerability in cilium (CVE-2026-41520). Confidential information can be exposed externally. Mitigation: upgrade to 1.17.15, 1.18.9, 1.19.3 or later.
Original description
The description as published by the source.
Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Prior to versions 1.17.15, 1.18.9, and 1.19.3, the output of cilium-bugtool can contain sensitive data when the tool is run against Cilium deployments with WireGuard encryption enabled. This issue has been patched in versions 1.17.15, 1.18.9, and 1.19.3.
Source: NIST National Vulnerability Database 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-2026-41520 has been found in cilium.
Confidential information can be exposed externally. CVSS score: 7.9/10.
What to do: upgrade cilium to 1.17.15, 1.18.9, 1.19.3 or later.
If unsure, ask your IT team or search "cilium CVE-2026-41520" on the vendor's site.
CVE-2026-41520 (cilium) — CWE-200 / CVSS v3 7.9
Attack vector: local / no user interaction
Patched: 1.17.15, 1.18.9, 1.19.3 — 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.
Information disclosure (CWE-200) exists in cilium.
Check the vendor advisory for the affected versions of cilium.
Severity: High (CVSS 7.9/10). Confidential information can be exposed externally.
Update to 1.17.15, 1.18.9, 1.19.3.
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 'cilium' . 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
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1Identify exposure identify
grep -r 'cilium' . | 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
cilium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 cilium to 1.17.15, 1.18.9, 1.19.3ステージング環境で 1.17.15, 1.18.9, 1.19.3 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 github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com
- web github.com
- web docs.cilium.io
- web github.com