CVE-2026-92760

MEDIUM 6.5

Shlink through 5.1.6 Mercure Token Authorization Bypass

CVSS Score

6.5

EPSS Score

0.0%

EPSS Percentile

0th

Shlink through 5.1.6 fails to enforce API key role restrictions when issuing Mercure subscription tokens, allowing restricted keys to subscribe to all topics. Attackers with author-only or domain-only keys can access the mercure-info endpoint to receive visit data including referrer, user agent, geolocation, and full short URL objects for URLs outside their authorization boundary.

CWE	CWE-863
Vendor	shlinkio
Product	shlink
Published	Sep 16, 2026

Stay Ahead of the Next One

Get instant alerts for shlinkio shlink

Be the first to know when new medium vulnerabilities affecting shlinkio shlink are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

shlinkio / shlink

0 ≤ 5.1.6

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/shlinkio/shlink/issues/2633 github.com: https://github.com/shlinkio/shlink github.com: https://github.com/shlinkio/shlink/blob/v5.1.6/module/Rest/src/Action/MercureInfoAction.php#L26-L42 github.com: https://github.com/shlinkio/shlink-common/blob/main/src/Mercure/LcobucciJwtProvider.php#L38-L41 vulncheck.com: https://www.vulncheck.com/advisories/shlink-through-5.1.6-mercure-token-authorization-bypass

Credits

George Chen