CVE-2026-91852 Apache Sling XSS: CWE-79 multiple raw-string break-outs and ReDOS in XSSImpl
An attacker can inject malicious scripts via raw-string break-outs in Apache Sling XSS, potentially executing code in user sessions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-91852?
CVE-2026-91852 is a medium-severity cross-site scripting vulnerability in Apache Sling XSS, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Apache Sling XSS.
This issue affects Apache Sling XSS: before 2.4.12.
Users are recommended to upgrade to version 2.4.12, which fixes the issue.
Weakness: CWE-79
Which versions are affected by CVE-2026-91852?
It affects 1 product.
Products include Apache Sling Xss Protection Api.
How do I fix CVE-2026-91852?
No fix has been published for CVE-2026-91852 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-91852 being exploited?
There is no known exploitation of CVE-2026-91852 in the wild and no public exploit code.
Other vulnerabilities in Apache Sling XSS
- CVE-2026-73192 Apache Sling XSS: XSS possible through XSSAPI.getValidHref()
- CVE-2026-91928 Apache Sling XSS: Sanitizer bypass, uncontrolled resource consumption and failure pf protection mechanisms
- CVE-2026-91999 Apache Sling XSS: Improper escaping in the XSS Webconsole plugin
- CVE-2026-92001 Apache Sling XSS: Missing parser resource limits
- CVE-2017-15717 Cross-site Scripting in Apache Sling XSS Protection API
Sources
Also known as GHSA-j583-7q6g-jm53.