CVE-2026-18736 json
Shlink Server-Side Request Forgery via Short URL Title Auto-Resolution
published 2026-08-03 3 mo ago modified 2026-10-23 16 d ago also EUVD-2026-52427
- cvss
- 5.0
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 26%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/theopaid/Server-side-request-forgery-through-short-URL-title-resolution-shlink- referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 5.3 | 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 |
| CNA | 3.1 | 5.0 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N |
| CNA | 4.0 | 5.3 | 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 |
Affected products
- shlinkio Shlink
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
github.com
/theopaid/Server-side-request-forgery-through-short-URL-title-resolution-shlink-
vendor-advisory, exploit
-
github.com
/shlinkio/shlink
product
-
vulncheck.com
/advisories/shlink-server-side-request-forgery-via-short-url-title-auto-resolution
third-party-advisory
Sources
- CVE List CVE-2026-18736
- NVD CVE-2026-18736
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