8.2
HIGH CVSS 3.1
CVE-2026-63135
YOURLS: Stored XSS in referrer statistics chart via crafted Referer header
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.

INFO

Published Date :

Aug. 21, 2026, 9:17 p.m.

Last Modified :

Aug. 21, 2026, 9:17 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-63135 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH [email protected]
Solution
Update YOURLS to version 1.10.4 to fix a cross-site scripting vulnerability.
  • Update YOURLS to version 1.10.4.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-63135.

URL Resource
https://github.com/YOURLS/YOURLS/commit/e1e93476655107e6caab34e52259eb1c91079ec7
https://github.com/YOURLS/YOURLS/pull/4107
https://github.com/YOURLS/YOURLS/releases/tag/1.10.4
https://github.com/YOURLS/YOURLS/security/advisories/GHSA-5h77-88j3-r659
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-63135 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-63135 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-63135 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-63135 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Aug. 21, 2026

    Action Type Old Value New Value
    Added Affected [{'vendor': 'YOURLS', 'product': 'YOURLS', 'versions': [{'status': 'affected', 'version': '>= 1.5.1, < 1.10.4'}]}]
    Added 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.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
    Added CWE CWE-79
    Added Reference https://github.com/YOURLS/YOURLS/commit/e1e93476655107e6caab34e52259eb1c91079ec7
    Added Reference https://github.com/YOURLS/YOURLS/pull/4107
    Added Reference https://github.com/YOURLS/YOURLS/releases/tag/1.10.4
    Added Reference https://github.com/YOURLS/YOURLS/security/advisories/GHSA-5h77-88j3-r659
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.