A flaw was found in PyPy's pyexpat module. A remote attacker can cause memory corruption by supplying a specially crafted Extensible Markup Language (XML) document to an application that processes external entity sub-parsers without keeping a reference to the parent parser. This situation triggers a use-after-free condition, where the parent parser's memory is released prematurely while still referenced by the sub-parser, resulting in invalid memory access during parsing.
Last checked: 2026-10-02 14:28 UTC
No exploitation evidence · CISA Coordinator (Assessed 2026-10-02 12:07 UTC)
Fix evidence last checked: 2026-09-29 17:36 UTC