CVE-2026-18736: Server-Side Request Forgery (SSRF) in shlinkio Shlink
Shlink version 2.6.0 contains a server-side request forgery (SSRF) vulnerability that allows authenticated API key holders to make the server perform arbitrary HTTP GET requests. This occurs when a crafted long URL is supplied during short URL creation with title auto-resolution enabled. The vulnerability can be exploited to access internal network resources, including cloud metadata endpoints, by leveraging redirects from public hosts. The vulnerability has a medium severity with a CVSS score of 5.3.
AI Analysis
Technical Summary
CVE-2026-18736 is an SSRF vulnerability in Shlink 2.6.0 where authenticated users with API keys can cause the server to issue arbitrary HTTP GET requests by submitting specially crafted long URLs during short URL creation when title auto-resolution is enabled. Attackers can exploit this to access internal network resources such as loopback addresses, link-local ranges, and cloud metadata services (e.g., 169.254.169.254) by using public hosts that redirect to these internal targets. The internal service information can be exfiltrated via the HTML title element returned in the short URL creation response.
Potential Impact
An attacker with a valid API key can leverage this SSRF vulnerability to make the Shlink server perform HTTP requests to internal network resources that are normally inaccessible externally. This can lead to information disclosure of internal services, including sensitive cloud metadata endpoints. The vulnerability is rated medium severity with a CVSS score of 5.3, indicating a moderate risk level.
Mitigation Recommendations
No official patch or remediation guidance is currently available for this vulnerability. Users should monitor the vendor advisory for updates. As the vulnerability requires authenticated API access and title auto-resolution enabled, consider restricting API key usage and disabling title auto-resolution as temporary mitigations until an official fix is released.
CVE-2026-18736: Server-Side Request Forgery (SSRF) in shlinkio Shlink
Description
Shlink version 2.6.0 contains a server-side request forgery (SSRF) vulnerability that allows authenticated API key holders to make the server perform arbitrary HTTP GET requests. This occurs when a crafted long URL is supplied during short URL creation with title auto-resolution enabled. The vulnerability can be exploited to access internal network resources, including cloud metadata endpoints, by leveraging redirects from public hosts. The vulnerability has a medium severity with a CVSS score of 5.3.
CVSS v4.0
Score 5.3medium
Affected software
shlinkio
Shlink
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-18736 is an SSRF vulnerability in Shlink 2.6.0 where authenticated users with API keys can cause the server to issue arbitrary HTTP GET requests by submitting specially crafted long URLs during short URL creation when title auto-resolution is enabled. Attackers can exploit this to access internal network resources such as loopback addresses, link-local ranges, and cloud metadata services (e.g., 169.254.169.254) by using public hosts that redirect to these internal targets. The internal service information can be exfiltrated via the HTML title element returned in the short URL creation response.
Potential Impact
An attacker with a valid API key can leverage this SSRF vulnerability to make the Shlink server perform HTTP requests to internal network resources that are normally inaccessible externally. This can lead to information disclosure of internal services, including sensitive cloud metadata endpoints. The vulnerability is rated medium severity with a CVSS score of 5.3, indicating a moderate risk level.
Mitigation Recommendations
No official patch or remediation guidance is currently available for this vulnerability. Users should monitor the vendor advisory for updates. As the vulnerability requires authenticated API access and title auto-resolution enabled, consider restricting API key usage and disabling title auto-resolution as temporary mitigations until an official fix is released.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-03T20:03:05.797Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a70fecabf32cb7a342e2070
Added to database: 08/03/2026, 20:49:14 UTC
Last enriched: 08/11/2026, 18:39:10 UTC
Last updated: 09/17/2026, 22:01:33 UTC
Views: 62
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