Authorization Flaw in github.com/cilium/cilium (CVE-2026-53935)
Summary
Vulnerability in github.com/cilium/cilium (CVE-2026-53935). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1.17.16, 1.18.10, 1.19.4 or later.
Original description
The description as published by the source.
Cilium is a networking, observability, and security solution. Prior to 1.17.16, from 1.18.2 to 1.18.9, and from 1.19.0 to 1.19.3, users with the ability to create CiliumLocalRedirectPolicies can specify arbitrary ClusterIPs via addressMatcher, enabling hijacking traffic to Services in any namespace and bypassing namespace scoping enforced by serviceMatcher; deleting such a policy can also corrupt Cilium internal service state and stop service translation for the affected Service. This issue is fixed in versions 1.17.16, 1.18.10, and 1.19.4.
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-2026-53935 has been found in github.com/cilium/cilium.
Risk of unauthorized operations or information disclosure. CVSS score: 6.9/10.
What to do: upgrade github.com/cilium/cilium to 1.17.16, 1.18.10, 1.19.4 or later.
If unsure, ask your IT team or search "github.com/cilium/cilium CVE-2026-53935" on the vendor's site.
CVE-2026-53935 (github.com/cilium/cilium) — CWE-863 / CVSS v3 6.9
Attack vector: adjacent-network / no user interaction
Patched: 1.17.16, 1.18.10, 1.19.4 — 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.
Incorrect authorization (CWE-863) exists in github.com/cilium/cilium.
Check the vendor advisory for the affected versions of github.com/cilium/cilium.
Severity: Medium (CVSS 6.9/10). Risk of unauthorized operations or information disclosure.
Update to 1.17.16, 1.18.10, 1.19.4.
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/cilium/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 'github.com/cilium/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
github.com/cilium/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 github.com/cilium/cilium to 1.17.16, 1.18.10, 1.19.4ステージング環境で 1.17.16, 1.18.10, 1.19.4 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
- patch github.com
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- web github.com