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Fencer Vulns
low 2.0

CVE-2026-6879 json

Quadratic Behavior in xml.etree.ElementPath Index Predicates

published 2026-07-28 3 mo ago modified 2026-10-24 15 d ago also BIT-libpython-2026-6879 , BIT-python-2026-6879 , BIT-python-min-2026-6879 , EUVD-2026-49850

cvss
2.0
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

`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.

Patch / fix

  • bitnami libpython 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7
  • bitnami python 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7
  • bitnami python-min 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7
  • Python Software Foundation CPython 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7, 3.15.0rc1
  • pypy3 Debian 14 8.0.0+dfsg-1
  • python3.13 Debian 13 3.13.5-2+deb13u5
  • python3.14 Debian 14 3.14.7-1

debian advisories DEBIAN-CVE-2026-6879

  • python3.13 hummingbird 1 3.13.15-1.hum1
  • python3.13-idle hummingbird 1 3.13.15-1.hum1
  • python3.13-libs hummingbird 1 3.13.15-1.hum1
  • python3.13-test hummingbird 1 3.13.15-1.hum1
  • python3.13-tkinter hummingbird 1 3.13.15-1.hum1
  • python3.13-freethreading hummingbird 1 3.13.15-1.hum1
  • python3 hummingbird 1 3.14.7-1.hum1
  • python3.14 hummingbird 1 3.14.7-1.hum1

red hat advisories RHSA-2026:54554RHSA-2026:54534RHSA-2026:48278RHSA-2026:48279RHSA-2026:48253RHSA-2026:48246

  • python3 SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +11 more 3.6.15-150300.10.129.1
  • python3-core SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +12 more 3.6.15-150300.10.129.1
  • python SLE Module for Package Hub 15 SP7 2.7.18-150000.133.1
  • python-base SLE Module for Package Hub 15 SP7 2.7.18-150000.133.1
  • python313 SLE Module for Python 3 15 SP7 3.13.15-150700.4.56.1
  • python313-core SLE Module for Python 3 15 SP7 3.13.15-150700.4.56.1
  • python3 SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 3.4.10-25.199.1
  • python3-base SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 3.4.10-25.199.1

suse advisories SUSE-SU-2026:4754-1SUSE-SU-2026:4744-1SUSE-SU-2026:4743-1SUSE-SU-2026:4633-1SUSE-SU-2026:4411-1SUSE-SU-2026:4401-1

  • python313 openSUSE Tumbleweed 3.13.15-1.1
  • python315 openSUSE Tumbleweed 3.15.0~rc2-1.1

opensuse advisories openSUSE-SU-2026:11817-1openSUSE-SU-2026:11748-1

  • python3 Alpine 3.24 3.14.7-r0

alpine advisories ALPINE-CVE-2026-6879

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python3 Azure Linux 3.0 3.12.9-14

azure linux advisories AZL-94299

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-6879 updated cvss 2.2

python: Python: Performance degradation in XML processing due to quadratic time complexity

  • Red Hat Hardened Images python3 3.14.6-2.2.hum1, python3.14 3.14.6-2.2.hum1, python3.10 3.10.20-3.2.hum1, python3.11 3.11.15-5.5.hum1, python3.12 3.12.13-3.8.hum1, python3.13 3.13.14-1.7.hum1, +1 more
    fixed: vendor fix RHSA-2026:48246

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 2.0 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
CNA 4.0 2.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
bitnami libpython
<3.10.21
>=3.11.0, <3.11.16
>=3.12.0, <3.12.14
>=3.13.0, <3.13.15
>=3.14.0, <3.14.7
3.10.21
3.11.16
3.12.14
3.13.15
3.14.7
bitnami python
<3.10.21
>=3.11.0, <3.11.16
>=3.12.0, <3.12.14
>=3.13.0, <3.13.15
>=3.14.0, <3.14.7
3.10.21
3.11.16
3.12.14
3.13.15
3.14.7
bitnami python-min
<3.10.21
>=3.11.0, <3.11.16
>=3.12.0, <3.12.14
>=3.13.0, <3.13.15
>=3.14.0, <3.14.7
3.10.21
3.11.16
3.12.14
3.13.15
3.14.7

Affected products

  • Python Software Foundation CPython

Classification

Weakness
  • CWE-407 Inefficient Algorithmic Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.