{"id":"CVE-2026-6879","summary":"Quadratic Behavior in xml.etree.ElementPath Index Predicates","details":"`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.","aliases":["PSF-2026-34"],"modified":"2026-07-31T03:49:08.732669296Z","published":"2026-07-28T13:46:30.650Z","database_specific":{"cna_assigner":"PSF","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6879.json","unresolved_ranges":[{"extracted_events":[{"fixed":"3.15.0"}],"source":"AFFECTED_FIELD"}]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6879.json"},{"type":"ADVISORY","url":"https://mail.python.org/archives/list/security-announce@python.org/thread/7YMZ6DDZVR26TJJBVO3RDNBAVGHNYAKR/"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6879"},{"type":"REPORT","url":"https://github.com/python/cpython/issues/152674"},{"type":"FIX","url":"https://github.com/python/cpython/commit/02c08e6b747ac43d0d866a4ffa916bedf3423f81"},{"type":"FIX","url":"https://github.com/python/cpython/commit/2ffab083782968a4d732738f4f1dff6bbd69d2b0"},{"type":"FIX","url":"https://github.com/python/cpython/commit/390337b8ba1658833fdef379e1739c9f9533a8db"},{"type":"FIX","url":"https://github.com/python/cpython/commit/cb409342a19f25656f62e679f8bac265fe1442c3"},{"type":"FIX","url":"https://github.com/python/cpython/pull/152676"},{"type":"PACKAGE","url":"https://github.com/python/cpython"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/python/cpython","events":[{"introduced":"0"},{"fixed":"2ffab083782968a4d732738f4f1dff6bbd69d2b0"}],"database_specific":{"source":"REFERENCES"}}],"versions":["v3.15.0b1","v3.15.0a8","v3.15.0a7","v3.15.0a6","v3.15.0a5","v3.15.0a4","v3.15.0a3","v3.15.0a2","v3.15.0a1","v3.14.0b1","v3.14.0a7","v3.14.0a6","v3.14.0a5","v3.14.0a4","v3.14.0a3","v3.14.0a2","v3.14.0a1","v3.13.0b1","v3.13.0a6","v3.13.0a5","v3.13.0a4","v3.13.0a3","v3.13.0a2","v3.13.0a1","v3.12.0b1","v3.12.0a7","v3.12.0a6","v3.12.0a5","v3.12.0a4","v3.12.0a3","v3.12.0a2","v3.12.0a1","v3.11.0b1","v3.11.0a7","v3.11.0a6","v3.11.0a5","v3.11.0a4","v3.11.0a3","v3.10.0a7","v3.10.0a1","v3.9.0a2","v3.7.0a2","v3.6.0b1","v3.6.0a3","v3.5.0b1","v3.5.0a4","v3.5.0a3","v3.5.0a2","v3.5.0a1","v3.4.0b3","v3.4.0b2","v3.4.0b1","v3.4.0a4","v3.4.0a3","v3.4.0a2","v3.4.0a1","v3.3.0rc3","v3.3.0rc2","v3.3.0rc1","v3.3.0b2","v3.3.0b1","v3.3.0a4","v3.3.0a3","v3.3.0a2","v3.2rc3","v3.2rc2","v3.2rc1","v3.2b2","v3.2b1","v3.2a4","v3.2a3","v3.2a2","v3.2a1","v3.1","v3.1rc2","v3.1rc1","v3.1b1","v3.1a2","v3.1a1","v3.0rc3","v3.0rc2","v3.0rc1","v3.0b3","v3.0b2","v3.0b1","v3.0a5","v3.0a4","v3.0a3","v3.0a2","v3.0a1","v2.4","v2.4c1","v2.4b2","v2.4b1","v2.4a3","v2.4a2","v2.4a1","v2.3c2","v2.3c1","v2.2a3","v2.1","v2.1c2","v2.1c1","v2.1b2","v2.1b1","v2.1a2","v2.1a1","v2.0","v2.0c1","v2.0b2","v2.0b1","v1.6a2","v1.6a1","v1.5.2","v1.5.2c1","v1.5.2b2","v1.5.2b1","v1.5.2a2","v1.5.2a1","v1.5.1","v1.5","v1.5b2","v1.5b1","v1.5a4","v1.5a3","v1.5a2","v1.5a1","v1.4","v1.4b3","v1.4b2","v1.4b1","v1.3","v1.3b1","v1.2","v1.2b4","v1.2b3","v1.2b2","v1.2b1","v1.1.1","v1.1","v1.0.2","v1.0.1","v0.9.9","v0.9.8"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-6879.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"}]}