Description
A bug in APR-util version 1.6.3 (and earlier) allows a stack recursion attack against any library consumer which parses XML from untrusted sources and uses the apr_xml_quote_elem() function. Users are recommended to upgrade to version 1.6.4, which fixes this issue.
Affected products
apache: apr-util
References2
- lists.apache.org/thread/hq27vj8yfno9tkwv0fpj6jksfzgxvth1 Mailing ListVendor Advisory
- www.openwall.com/lists/oss-security/2026/08/06/9 Mailing ListThird Party Advisory
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H - EPSS — exploit probability
- 0% percentile: 40 · as of 12 November 2026
- CWE
- CWE-674
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.