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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products
pypy:pypy
References 4
https://doc.pypy.org/release-v8.0.0.html
Release Notes
https://github.com/pypy/pypy/releases/tag/release-pypy3.12-v8.0.0
3.12 Release Tag
https://github.com/pypy/pypy/releases/tag/release-pypy3.11-v8.0.0
3.11 Release Tag
https://www.vulncheck.com/advisories/pypy-pyexpat-externalentityparsercreate-us…
NVD