PyPy up to 3.11.15/3.12.13 pyexpat module ExternalEntityParserCreate use after free

Summaryinfo

A vulnerability, which was classified as critical, has been found in PyPy up to 3.11.15/3.12.13. The impacted element is the function ExternalEntityParserCreate of the component pyexpat module. Performing a manipulation results in use after free. This vulnerability was named CVE-2026-76875. The attack may be initiated remotely. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in PyPy up to 3.11.15/3.12.13. This affects the function ExternalEntityParserCreate of the component pyexpat module. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

PyPy before versions 3.11.16 and 3.12.14 contains a use-after-free vulnerability in the pyexpat module's ExternalEntityParserCreate function that allows attackers to corrupt memory by supplying a crafted XML document to applications that create external-entity sub-parsers without retaining a reference to the parent parser. The child parser retains a raw C back-pointer to the parent parser struct while PyPy's tracing garbage collector can free the parent's C struct, causing bundled libexpat to dereference the freed pointer on every parsed token, producing memory corruption.

It is possible to read the advisory at doc.pypy.org. This vulnerability is uniquely identified as CVE-2026-76875 since 08/19/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 3.11.16 or 3.12.14 eliminates this vulnerability.

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Productinfo

Name

• PyPy

Version

• 3.11.0
• 3.11.1
• 3.11.2
• 3.11.3
• 3.11.4
• 3.11.5
• 3.11.6
• 3.11.7
• 3.11.8
• 3.11.9
• 3.11.10
• 3.11.11
• 3.11.12
• 3.11.13
• 3.11.14
• 3.11.15
• 3.12.0
• 3.12.1
• 3.12.2
• 3.12.3
• 3.12.4
• 3.12.5
• 3.12.6
• 3.12.7
• 3.12.8
• 3.12.9
• 3.12.10
• 3.12.11
• 3.12.12
• 3.12.13

CPE 2.3info

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CPE 2.2info

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