Is CVE-2026-7210 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-7210 being exploited in the wild.

How severe is CVE-2026-7210?

Critical severity, with a CVSS score of 9.8, published 11 May 2026.

Which products and versions are affected?

Python Software Foundation CPython 3.10, 3.11, 3.12, 3.13, 3.14, 3.10, 3.11, 3.12, 3.13, 3.14, 3.15.

Is there a fix for CVE-2026-7210?

A patch was published on 2026-05-10: Fix merged into CPython main branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-7210 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-7210?

Check whether you run Libexpat Project Libexpat or Python Software Foundation CPython at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-7210: Python CPython denial of service in XML parsers

CVE-2026-7210 · Severity: critical · CVSS 9.8 · Published 2026-05-11

A vulnerability exists in Python's standard XML parsing libraries, which are used by many applications to process data. An attacker can send a specially crafted XML document to cause a 'hash flooding' attack, which consumes excessive system resources. This can lead to a denial-of-service (DoS) condition, making the affected application or service slow or completely unresponsive.

Technologies: Libexpat Project Libexpat, Python Software Foundation CPython. Vendors: Libexpat Project, Python Software Foundation.

Quick answers

Is CVE-2026-7210 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-7210 being exploited in the wild.
How severe is CVE-2026-7210?: Critical severity, with a CVSS score of 9.8, published 11 May 2026.
Which products and versions are affected?: Python Software Foundation CPython 3.10, 3.11, 3.12, 3.13, 3.14, 3.10, 3.11, 3.12, 3.13, 3.14, 3.15.
Is there a fix for CVE-2026-7210?: A patch was published on 2026-05-10: Fix merged into CPython main branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-7210 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-7210?: Check whether you run Libexpat Project Libexpat or Python Software Foundation CPython at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The pyexpat and _elementtree modules in CPython use insufficient entropy (only 4 to 8 bytes) when calling XML_SetHashSalt to protect against hash-flooding attacks. This weakness allows an attacker to craft XML documents that cause hash collisions in the underlying Expat parser, leading to high CPU consumption and denial-of-service. The fix involves updating CPython to use the newer XML_SetHashSalt16Bytes API introduced in libexpat 2.8.0, which allows for 16 bytes of entropy. Full mitigation requires both patching CPython and ensuring the system is linked against libexpat 2.8.0 or later.

Affected products

Python Software Foundation CPython 3.10, 3.11, 3.12, 3.13, 3.14

Timeline

2026-04-26: disclosed: Issue reported on CPython GitHub repository
2026-05-10: patched: Fix merged into CPython main branch
2026-05-11: advisory: Official security announcement published

References

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