CVE-2026-6879Quadratic Behavior in xml.etree.ElementPath Index Predicates
Updated under an hour ago ()
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It affects Python Software Foundation CPython. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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`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.
- CVSS
- 2.0 LOW (v4.0, CNA)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
- Weakness (CWE)
- CWE-407
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- PSF
- NVD analysis
- Awaiting Analysis
- Record last updated
- Aug 12, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Python Software Foundation CPython python_software_foundation:cpython (from the name) | before 3.10.21; from 3.11.0 before 3.11.16; from 3.12.0 before 3.12.14; from 3.13.0 before 3.13.15; from 3.14.0 before 3.14.7; from 3.15.0a1 before 3.15.0rc1 | CNA record |
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
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.