Vulnerability in excon (CVE-2026-54171)
Summary
Vulnerability in excon (CVE-2026-54171). Confidential information can be exposed externally. Mitigation: upgrade to 1.5.0 or later.
Original description
The description as published by the source.
Excon is usable, fast, simple HTTP 1.1 for Ruby. Prior to 1.5.0, Excon's RedirectFollower middleware failed to strip additional sensitive headers when following redirects and did not provide a custom list of headers to strip. This could cause inadvertent leakage of sensitive data when the initial request includes header information that is not intended for the new target. This issue is fixed in version 1.5.0.
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-2026-54171 has been found in excon.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: upgrade excon to 1.5.0 or later.
If unsure, ask your IT team or search "excon CVE-2026-54171" on the vendor's site.
CVE-2026-54171 (excon) — CWE-201 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated
Patched: 1.5.0 — apply immediately
Workaround: Users can backport the fix to a custom redirect follower middleware.
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-201) exists in excon.
Check the vendor advisory for the affected versions of excon.
Severity: Medium (CVSS 6.5/10). Confidential information can be exposed externally.
Update to 1.5.0.
Workaround: Users can backport the fix to a custom redirect follower middleware.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'excon' . 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 'excon' . | 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
exconを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
Users can backport the [fix](https://github.com/excon/excon/commit/ea89a35308a12f4b791b6c50f2cbd33f94889fa3) to a custom redirect follower middleware.パッチが適用されるまでの応急処置として、Users can backport the fix to a custom redirect follower middleware. を実施。回避策の副作用 (機能低下) を確認した上で。
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3Apply patch patch
Upgrade excon to 1.5.0ステージング環境で 1.5.0 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。
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4Post-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
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-54171 ruby-excon
- Ubuntu UBUNTU-CVE-2026-54171 ruby-excon
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- patch github.com
- patch github.com
- web github.com
- web cve.org
- web github.com