SSRF (Server-Side Request Forgery) in Shlink (CVE-2026-18736)
Summary
SSRF in Shlink (CVE-2026-18736). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
Shlink contains a server-side request forgery vulnerability that allows authenticated API key holders to cause the server to issue arbitrary HTTP GET requests by supplying a crafted long URL during short URL creation with title auto-resolution enabled. Attackers can submit URLs pointing to public hosts that redirect to internal targets, including loopback addresses, link-local ranges, and cloud metadata endpoints such as 169.254.169.254, to exfiltrate internal service information via the HTML title element returned in the short URL creation response.
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-2026-18736 has been found in Shlink.
Risk of unauthorized operations or information disclosure. CVSS score: 5.0/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Shlink CVE-2026-18736" on the vendor's site.
CVE-2026-18736 (Shlink) — CWE-918 / CVSS v3 5.0
Attack vector: remote (network-reachable) / no user interaction
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.
SSRF (CWE-918) exists in Shlink.
Check the vendor advisory for the affected versions of Shlink.
Severity: Medium (CVSS 5.0/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
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 'Shlink' . 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
-
1Identify exposure identify
grep -r 'Shlink' . | 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
Shlinkを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-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。
References
- web nvd.nist.gov
- web disclosure@vulncheck.com
- web github.com
- web disclosure@vulncheck.com
- web github.com