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CVE-2026-18737: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') in shlinkio Shlink

0
High
VulnerabilityCVE-2026-18737cvecve-2026-18737
Published: 08/03/2026 (08/03/2026, 20:40:28 UTC)
Source: CVE Database V5
Vendor/Project: shlinkio
Product: Shlink

Description

Shlink contains a blind SQL injection vulnerability that allows any authenticated API key holder to inject arbitrary SQL fragments by supplying an unvalidated direction value in the orderBy query parameter of the tag statistics endpoint. Attackers can craft a malicious direction string containing SQL subqueries that flows unsanitized into a Doctrine QueryBuilder ORDER BY clause, enabling time-based, boolean-oracle, and error-based extraction of sensitive data including long URLs, visitor records, IP addresses, geolocation data, user agents, and hashed API key secrets from any tenant.

CVSS v4.0

Score 7.1high

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vuln. Confidentiality
High
Vuln. Integrity
None
Vuln. Availability
None
Subsq. Confidentiality
None
Subsq. Integrity
None
Subsq. Availability
None
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Affected software

shlinkio

Shlink

Affected versions
>=3.3.1 <=5.1.5
GitHub Actionsmore threats →ai
shlinkio/shlink
pkg:github/shlinkio/shlink
Affected versions
=3.3.1

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 08/11/2026, 17:53:34 UTC

Technical Analysis

CVE-2026-18737 is a blind SQL injection vulnerability affecting Shlink version 3.3.1. The flaw arises because the orderBy query parameter's direction value in the tag statistics endpoint is not properly sanitized before being used in a Doctrine QueryBuilder ORDER BY clause. An authenticated attacker with an API key can inject SQL subqueries, enabling time-based, boolean-oracle, and error-based data extraction techniques. This can expose sensitive tenant data including URLs, visitor information, IP addresses, geolocation, user agents, and hashed API keys.

Potential Impact

An attacker with an authenticated API key can exploit this vulnerability to perform blind SQL injection attacks, potentially extracting sensitive data from the database. This includes long URLs, visitor records, IP addresses, geolocation data, user agents, and hashed API key secrets for any tenant. The vulnerability compromises confidentiality of sensitive information stored by Shlink.

Mitigation Recommendations

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict API key access to trusted users only and monitor for suspicious activity related to the tag statistics endpoint. Avoid using untrusted input in the orderBy query parameter.

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Technical Details

Data Version
5.2
Assigner Short Name
VulnCheck
Date Reserved
2026-08-03T20:03:39.501Z
Cvss Version
4.0
State
PUBLISHED

Threat ID: 6a70fecabf32cb7a342e2075

Added to database: 08/03/2026, 20:49:14 UTC

Last enriched: 08/11/2026, 17:53:34 UTC

Last updated: 09/17/2026, 22:01:33 UTC

Views: 62

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