Vulnerability in github.com/dadrus/heimdall (CVE-2026-42272)
Summary
Vulnerability in github.com/dadrus/heimdall (CVE-2026-42272). Risk of unauthorized operations or information disclosure. Exploitable via allow_encoded_slashes. Mitigation: upgrade to 0.17.14 or later.
Original description
The description as published by the source.
Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.14, Heimdall handles URL-encoded slashes (%2F) in a case-sensitive manner, while percent-encoding is defined to be case-insensitive. As a result, the lowercase equivalent (%2f) is not recognized and therefore not processed as expected when allow_encoded_slashes is set to off (the default setting). This discrepancy can lead to differences in how request paths are interpreted by heimdall and upstream components, which may result in authorization bypass. This issue has been patched in version 0.17.14.
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-2026-42272 has been found in github.com/dadrus/heimdall.
Attackers can target a specific entry point like allow_encoded_slashes over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade github.com/dadrus/heimdall to 0.17.14 or later.
If unsure, ask your IT team or search "github.com/dadrus/heimdall CVE-2026-42272" on the vendor's site.
CVE-2026-42272 (github.com/dadrus/heimdall) — CWE-178
Attack surface: allow_encoded_slashes / off
Patched: 0.17.14 — 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-178) exists in github.com/dadrus/heimdall. Attackers reach the vulnerable code path via allow_encoded_slashes.
Check the vendor advisory for the affected versions of github.com/dadrus/heimdall. Attack surface: allow_encoded_slashes / off.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 0.17.14.
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/dadrus/heimdall' . 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/dadrus/heimdall' . | 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/dadrus/heimdall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/dadrus/heimdall to 0.17.14ステージング環境で 0.17.14 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
- patch github.com
- patch github.com
- web github.com
- web github.com