CVE-2026-63135 — HIGH (8.2)

Vulnerability 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.

CVSS Score

8.2

HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality

LOW

Integrity

HIGH

Availability

NONE

Related Weaknesses (CWE)

CWE-79

References

FAQ

What is CVE-2026-63135?

CVE-2026-63135 is a vulnerability with a CVSS score of 8.2 (HIGH). 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...

How severe is CVE-2026-63135?

CVE-2026-63135 has been rated HIGH with a CVSS base score of 8.2/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-63135?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.