Description
Improper restriction of recursive entity references in DTDs ('XML entity expansion') 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.
Affected products
apache: sling xss protection api
References2
- lists.apache.org/thread/m52jll26vc8g5jokbg0xt062o09wkghr Mailing ListVendor Advisory
- www.openwall.com/lists/oss-security/2026/09/23/15 Mailing ListThird Party Advisory
Metrics
- CVSS 3.1
-
6.1
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - EPSS — exploit probability
- 1% percentile: 48 · as of 9 November 2026
- CWE
- CWE-776
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.