CVE-2026-26209

The CVE-2026-26209 issue affects the Python library cbor2 (including the C extension _cbor2) prior to version 5.9.0. The root cause is uncontrolled recursion when decoding deeply nested CBOR structures, as the C extension relies on Python’s Py_EnterRecursiveCall rather than a data-driven depth li...

CVE-2026-26209

cbor2 provides encoding and decoding for the Concise Binary Object Representation CBOR serialization format. Versions prior to 5.9.0 are vulnerable to a Denial of Service DoS attack caused by uncontrolled recursion when decoding deeply nested CBOR structures. This vulnerability affects both the...