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CVE-2026-7210

The expat and elementtree parsers use insufficient entropy for XML hash-flooding protection

HIGH
7.5
CVSS Score
Published: May 11, 2026 at 05:19 PM UTC
Updated: October 26, 2026 at 06:10 PM UTC
1 product affected across 1 vendorPython

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Severity
HIGH7.5
Exploit prediction
EPSS 0.7%
SSVC
No known exploit

Description

`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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Python· Python
95%
v < 3.13.143.14.0 ≤ v < 3.14.63.11.03.12.03.13.03.14.03.15.03.15.0 alpha13.15.0 alpha23.15.0 alpha33.15.0 alpha43.15.0 alpha53.15.0 alpha63.15.0 alpha73.15.0 alpha83.15.0 beta13.15.0a1
Affected range stops below 3.10.22, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.11.16, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.12.14, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.13.14, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.14.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.15.0b2, so it looks safe — our inference, not a vendor statement

References (12)

Vendor AdvisoryMailing ListThird Party Advisory
Source: cverecord
https://mail.python.org/archives/list/[email protected]/thread/PNY5OMBDPM2FRUZTWFFPJ6LISWKV627K/
PatchIssue Tracking
Source: cverecord
https://github.com/python/cpython/pull/149023
Issue Tracking
Source: cverecord
https://github.com/python/cpython/issues/149018
Mailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/05/11/13
Mailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/05/11/8
Patch
Source: [email protected]
https://github.com/python/cpython/commit/24b8f12544468e4cedf5bfbe25442fcd495391e4
Patch
Source: [email protected]
https://github.com/python/cpython/commit/3573b3b1ecbd99030a0b18658e1bfece771b2566
Patch
Source: [email protected]
https://github.com/python/cpython/commit/eeea765cb9d8f1fc3d8918b272ac3c477983f27a

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGH[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-331

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