5.0
MEDIUM CVSS 4.0
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 :

Aug. 3, 2026, 9:16 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-18736 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
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 or restrict URL access to prevent SSRF.
  • 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.

URL Resource
https://github.com/shlinkio/shlink
https://github.com/theopaid/Server-side-request-forgery-through-short-URL-title-resolution-shlink-
https://www.vulncheck.com/advisories/shlink-server-side-request-forgery-via-short-url-title-auto-resolution
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.

  • 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
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.