CVE-2026-18736
Shlink Server-Side Request Forgery via Short URL Title Auto-Resolution
Description
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.
INFO
Published Date :
Aug. 3, 2026, 9:16 p.m.
Last Modified :
Oct. 23, 2026, 9:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Disable title auto-resolution for URL creation.
- Restrict access to internal network resources.
- Update Shlink to the latest version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-18736.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-18736 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-18736
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-18736 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-18736 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 23, 2026
Action Type Old Value New Value Added Translation Title: Shlink de shlinkio, Description: Shlink contiene una vulnerabilidad de falsificación de petición del lado del servidor que permite a los titulares de claves API autenticados hacer que el servidor emita peticiones HTTP GET arbitrarias al proporcionar una URL larga manipulada durante la creación de URL cortas con la resolución automática de títulos habilitada. Los atacantes pueden enviar URLs que apunten a hosts públicos que redirijan a objetivos internos, incluyendo direcciones de bucle invertido, rangos link-local y puntos finales de metadatos en la nube como 169.254.169.254, para exfiltrar información de servicios internos a través del elemento de título HTML devuelto en la respuesta de creación de URL corta. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 04, 2026
Action Type Old Value New Value Added Reference https://github.com/theopaid/Server-side-request-forgery-through-short-URL-title-resolution-shlink- Added SSVC {'id': 'CVE-2026-18736', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-04T13:44:56.395426Z'} -
New CVE Received by [email protected]
Aug. 03, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'shlinkio', 'product': 'Shlink', 'versions': [{'status': 'affected', 'version': '2.6.0', 'versionType': 'git', 'lessThanOrEqual': '5.1.5'}], 'defaultStatus': 'affected'}] Added Description 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. Added CVSS V4.0 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 Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N Added CWE CWE-918 Added Reference https://github.com/shlinkio/shlink Added Reference https://github.com/theopaid/Server-side-request-forgery-through-short-URL-title-resolution-shlink- Added Reference https://www.vulncheck.com/advisories/shlink-server-side-request-forgery-via-short-url-title-auto-resolution