Python · Cpython · CVE-2026-6879
**Name of the Vulnerable Software and Affected Versions**
The product name cannot be determined (affected versions not specified)
**Description**
Certain functions exhibit quadratic time complexity, denoted as `O(n^2)`, when processing XML documents containing numerous siblings with the same tag. This occurs specifically when using XPath index predicates such as `[1]`, `[last()]`, or `[last()-N]`. The affected functions include `Element.findall()` and fully-consumed `Element.iterfind()`. Additionally, `Element.find()` is impacted when the first match is located near the end of the sibling list, such as when using `[last()]` or `[last()-N]`, although `.//item[1]` short-circuits after the first match.
**Recommendations**
At the moment, there is no information about a newer version that contains a fix for this vulnerability.