Reported

October 12, 2024

Issued

October 14, 2024

Package

pyo3 (crates.io)

Type

Vulnerability

Categories

• memory-corruption

Keywords

#use-after-free

References

• https://github.com/PyO3/pyo3/pull/4590

Patched

• >=0.22.4

Unaffected

• <0.22.0

Affected Functions

Version

pyo3::types::PyWeakrefMethods::get_object_borrowed

• <0.22.4, >=0.22.0

pyo3::types::PyWeakrefMethods::upgrade_borrowed

• <0.22.4, >=0.22.0

pyo3::types::PyWeakrefMethods::upgrade_borrowed_as

• <0.22.4, >=0.22.0

pyo3::types::PyWeakrefMethods::upgrade_borrowed_as_exact

• <0.22.4, >=0.22.0

pyo3::types::PyWeakrefMethods::upgrade_borrowed_as_unchecked

• <0.22.4, >=0.22.0

Description

The family of functions to read "borrowed" values from Python weak references were fundamentally unsound, because the weak reference does itself not have ownership of the value. At any point the last strong reference could be cleared and the borrowed value would become dangling.

In PyO3 0.22.4 these functions have all been deprecated and patched to leak a strong reference as a mitigation. PyO3 0.23 will remove these functions entirely.

Advisory available under CC0-1.0 license.