Vulnerability · Published Aug 21, 2026 · Assigned by GitHub_M
CVE-2026-63135YOURLS: Stored XSS in referrer statistics chart via crafted Referer header
High 8.2
In plain English
A high-severity cross-site scripting in YOURLS from YOURLS. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
YOURLS is a self-hosted, customizable URL shortener written in PHP. From 1.5.1 until 1.10.4, YOURLS stores the HTTP Referer header through yourls_get_referrer(), yourls_sanitize_url_safe(), and yourls_log_redirect(), then aggregates the value in yourls-infos.php and passes the derived domain through yourls_get_domain(), yourls_stats_pie(), and yourls_google_array_to_data_table(). The chart builder concatenates labels into inline JavaScript without JavaScript-string escaping, so an unauthenticated attacker can poison the statistics of an existing short URL with a crafted referrer. When an administrator or public stats-page viewer opens the affected statistics page, attacker-controlled JavaScript executes in the YOURLS origin and can access admin-visible data, the API signature token, and privileged same-origin actions. This issue is fixed in version 1.10.4.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Packagist | yourls/yourls | 1.10.4 | GHSA-5h77-88j3-r659 |
Affected products (as reported)
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
References
- https://github.com/YOURLS/YOURLS/security/advisories/GHSA-5h77-88j3-r659 x_refsource_CONFIRM
- https://github.com/YOURLS/YOURLS/pull/4107 x_refsource_MISC
- https://github.com/YOURLS/YOURLS/commit/e1e93476655107e6caab34e52259eb1c91079ec7 x_refsource_MISC
- https://github.com/YOURLS/YOURLS/releases/tag/1.10.4 x_refsource_MISC