# CVE-2026-91852: Apache Sling XSS cross-site scripting vulnerability

Source: https://junglewise.ai/threats/cve-2026-91852-improper-neutralization-of-input-during-web-page-generation-cross  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-23. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-91852 · Severity: medium · CVSS 6.1 · Published 2026-09-23

Apache Sling XSS is a library component used to prevent cross-site scripting attacks in web applications. This vulnerability is itself a cross-site scripting flaw in the library's input handling, allowing attackers to inject malicious scripts into web pages. An organization relying on this library for XSS protection may unknowingly expose users to script injection attacks.

Technologies: [Apache Sling XSS](https://junglewise.ai/threats/technologies/sling-xss). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache).

## Quick answers

**Is CVE-2026-91852 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-91852 being exploited in the wild.

**How severe is CVE-2026-91852?** Medium severity, with a CVSS score of 6.1, published 23 September 2026.

**Which products and versions are affected?** Apache Sling XSS before 2.4.12.

**Is there a fix for CVE-2026-91852?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-91852 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-91852?** Check whether you run Apache Sling XSS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an improper neutralization of user input during web page generation (CWE-79), affecting Apache Sling XSS versions before 2.4.12. The flaw allows malicious input to bypass XSS protections and be rendered as script code in generated web pages. A fix is available in version 2.4.12 and later.

## Affected products

- Apache Sling XSS before 2.4.12

## Timeline

- 2026-09-23: disclosed

## References

- [https://lists.apache.org/thread/nd0ncdk5qb9gqvn0s10rmhnbk887k1qo](https://lists.apache.org/thread/nd0ncdk5qb9gqvn0s10rmhnbk887k1qo)
- [https://sling.apache.org/news.html](https://sling.apache.org/news.html)

## Related threats

- [Apache Sling XSS cross-site scripting in getStyleToken](https://junglewise.ai/threats/cve-2026-123765-improper-neutralization-of-input-during-web-page-generation)
- [Apache Sling XSS XML entity expansion vulnerability](https://junglewise.ai/threats/cve-2026-92001-improper-restriction-of-recursive-entity-references-in-dtds-xml)
- [Apache Sling XSS cross-site scripting in web console plugin](https://junglewise.ai/threats/cve-2026-91999-improper-neutralization-of-input-during-web-page-generation-cross)
- [Apache Sling XSS cross-site scripting vulnerability](https://junglewise.ai/threats/cve-2026-91928-improper-neutralization-of-input-during-web-page-generation-cross)
- [Apache Sling XSS reflected XSS in getValidHref()](https://junglewise.ai/threats/cve-2026-73192-an-improper-neutralization-of-input-during-web-page-generation)