What is CVE-2026-91852?

CVE-2026-91852 is a medium-severity vulnerability in Apache Sling Xss Protection API, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-09-23.

How severe is CVE-2026-91852?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Apache Sling Xss Protection API

CVE-2026-91852

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-09-23 · last modified 2026-09-30.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.008 (56.5th percentile), scored 2026-11-04.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.008 · change: +0.003

Affected products

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

sling.apache.org/news.html (Product, vendor-advisory)
lists.apache.org/thread/nd0ncdk5qb9gqvn0s10rmhnbk887k1qo (vendor-advisory, Mailing List, Vendor Advisory)
af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2026-91852?: CVE-2026-91852 is a medium-severity vulnerability in Apache Sling Xss Protection API, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-09-23.
How severe is CVE-2026-91852?: Medium severity. CVSS v3 base score is 6.1 out of 10.