CVE-2026-18736

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.

Published 03 Aug 2026, 21:16 UTC Last modified 03 Aug 2026, 21:16 UTC

5.3

CVSS 4.0 MEDIUM base score

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack profile

The conditions required to exploit this vulnerability and its potential impact.

Attack vector Network

Attack complexity Low

Privileges required Low

User interaction None

Scope Not assessed

Confidentiality Not assessed

Integrity Not assessed

Availability Not assessed

Affected products

Product applicability statements supplied with the NVD record.

NVD has not published structured affected-product data for this record.

Weakness classification

CWE categories help security teams group the underlying software weakness.

CWECWE-918

Source references

External advisories, patches and technical reports attached to this CVE record.

NVD National Vulnerability Database recordnvd.nist.gov 01 Technical reference disclosure@vulncheck.com 02 Technical reference disclosure@vulncheck.com 03 Technical reference disclosure@vulncheck.com