Python CPython up to 3.14.x XML xml.parsers.Expat/xml.etree.ElementTree entropy

CVSS Meta Temp Score
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, was found in Python CPython up to 3.14.x. This affects the function xml.parsers.Expat/xml.etree.ElementTree of the component XML Handler. The manipulation results in entropy. This vulnerability is known as CVE-2026-7210. It is possible to launch the attack remotely. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in Python CPython up to 3.14.x. Affected is the function xml.parsers.Expat/xml.etree.ElementTree of the component XML Handler. The manipulation with an unknown input leads to a entropy vulnerability. CWE is classifying the issue as CWE-331. The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others. This is going to have an impact on availability. CVE summarizes:

`xml.parsers.expat` and `xml.etree.ElementTree` use insufficient entropy for Expat hash-flooding protection, which allows a crafted XML document to trigger hash flooding.\r\n\r\nFully mitigating this vulnerability requires both updating libexpat to 2.8.0 or later and applying this patch.

The advisory is shared for download at mail.python.org. This vulnerability is traded as CVE-2026-7210 since 04/27/2026. The exploitability is told to be difficult. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1600.001.

The vulnerability scanner Nessus provides a plugin with the ID 327402 (Amazon Linux 2023 : python3.11, python3.11-devel, python3.11-idle (ALAS2023-2026-1930)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.15.0 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (327402), EUVD (EUVD-2026-29178) and CERT Bund (WID-SEC-2026-1472). Once again VulDB remains the best source for vulnerability data.

Affected

  • Open Source Python

Productinfo

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Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Entropy
CWE: CWE-331 / CWE-330 / CWE-310
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 327402
Nessus Name: Amazon Linux 2023 : python3.11, python3.11-devel, python3.11-idle (ALAS2023-2026-1930)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: CPython 3.15.0
Patch: github.com

Timelineinfo

04/27/2026 CVE reserved
05/11/2026 +14 days Advisory disclosed
05/11/2026 +0 days VulDB entry created
08/13/2026 +94 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: 149018
Status: Confirmed

CVE: CVE-2026-7210 (🔒)
GCVE (CVE): GCVE-0-2026-7210
GCVE (VulDB): GCVE-100-362700
EUVD: 🔒
CERT Bund: WID-SEC-2026-1472 - CPython: Schwachstelle ermöglicht Denial of Service

Entryinfo

Created: 05/11/2026 20:27
Updated: 08/13/2026 04:36
Changes: 05/11/2026 20:27 (71), 05/12/2026 13:54 (7), 05/18/2026 13:13 (11), 06/15/2026 21:44 (5), 07/18/2026 08:55 (2), 08/13/2026 04:36 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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