Quick answers
- Is CVE-2026-18737 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-18737 being exploited in the wild.
- How severe is CVE-2026-18737?
- Medium severity, with a CVSS score of 6.5, published 3 August 2026.
- Which products and versions are affected?
- Shlink 3.3.1 through 5.1.5.
- Is there a fix for CVE-2026-18737?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-18737 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-18737?
- Check whether you run Shlink at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
This is a blind SQL injection vulnerability (CWE-89) in the tag statistics endpoint (`GET /rest/v{n}/tags/stats`). The orderBy query parameter accepts a field-direction format, where the field is validated against an allowlist but the direction value is not sanitized. The unvalidated direction string is concatenated directly into a Doctrine QueryBuilder ORDER BY clause that executes as a native SQL query. An attacker with any valid API key (regardless of role restrictions) can inject SQL subqueries to perform time-based, boolean-oracle, and error-based data extraction. The vulnerability affects versions 3.3.1 through at least 5.1.5 with no patch available. The fix requires validating the direction parameter against allowed values (ASC/DESC) before query execution, similar to the validation applied in the short URLs endpoint.
Affected products
- Shlink Shlink 3.3.1 through 5.1.5
Timeline
- 2026-08-03: disclosed: CVE-2026-18737 published on NVD