CVE-2026-7210

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.

CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0006

Probability of exploitation

0.19%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-331 CWE-331

Affected Products

Vendor	Product	Versions
libexpat_project	libexpat	< 2.8.0

References

Advisories & Patches

https://github.com/python/cpython/pull/149023

Other References

https://github.com/python/cpython/issues/149018 https://mail.python.org/archives/list/[email protected]/thread/PNY5OMBDPM2FRUZTWFFPJ6LISWKV627K/ http://www.openwall.com/lists/oss-security/2026/05/11/13 http://www.openwall.com/lists/oss-security/2026/05/11/8

Frequently Asked Questions

What is CVE-2026-7210? +

`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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-7210? +

CVE-2026-7210 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0006, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-7210? +

CVE-2026-7210 affects products from libexpat_project, specifically: libexpat. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-7210? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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