`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.

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Tue, 28 Jul 2026 16:15:00 +0000

Type Values Removed Values Added
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.
Title Quadratic Behavior in xml.etree.ElementPath Index Predicates
Weaknesses CWE-407
References
Metrics cvssV4_0

{'score': 2, 'vector': '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'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: PSF

Published:

Updated: 2026-07-28T14:54:07.235Z

Reserved: 2026-04-22T18:26:56.743Z

Link: CVE-2026-6879

cve-icon Vulnrichment

Updated: 2026-07-28T14:50:05.923Z

cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses