CVE-2026-6879
Quadratic Behavior in xml.etree.ElementPath Index Predicates
- State
- Published
- Severity
- 2.0 Low
- Published
- Jul 28, 2026
- Updated
- Aug 13, 2026
- Reserved
- Apr 22, 2026
Description
`Element.findall()` and fully-consumed `Element.iterfind()` exhibit `O(n^2)` time complexity when using XPath index predicates (e.g. `[1]`, `[last()]`, `[last()-N]`) on XML documents with many same-tag siblings. `Element.find()` is only affected when the first match is near the end of the sibling list, such as with `[last()]` or `[last()-N]`; `.//item[1]` short-circuits after the first match.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 2.0 Low | CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N | PSF |
Weaknesses
- CWE-407 Inefficient Algorithmic Complexity
Affected Products
| Product | Versions |
|---|---|
CPythonPython Software Foundation |
|
References
- https://github.com/python/cpython/pull/152676patch
- https://github.com/python/cpython/issues/152674issue-tracking
- https://mail.python.org/archives/list/security-announce@python.org/thread/7YMZ6DDZVR26TJJBVO3RDNBAVGHNYAKR/vendor-advisory
- https://github.com/python/cpython/commit/2ffab083782968a4d732738f4f1dff6bbd69d2b0patch
- https://github.com/python/cpython/commit/02c08e6b747ac43d0d866a4ffa916bedf3423f81patch
- https://github.com/python/cpython/commit/390337b8ba1658833fdef379e1739c9f9533a8dbpatch
- https://github.com/python/cpython/commit/cb409342a19f25656f62e679f8bac265fe1442c3patch
- https://github.com/python/cpython/commit/96510a3758f4a075f43223afdee3b6ee1a7a7f02patch
- https://github.com/python/cpython/commit/037965c00a427cba5c05447efadc67c51a492e85patch
- https://github.com/python/cpython/commit/0583f24ae678993e3f7939f51ad5bcae5ad9dc70patch
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