CVE-2026-48506
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
MessagePack for C# has a vulnerability that allows recursive descent into nested arrays and maps without proper depth checks. This can lead to unbounded recursion and a StackOverflowException.
Risk Assessment
Organizations may experience performance issues or application crashes due to uncontrolled recursion, potentially leading to service outages.
Recommendation
It is recommended to upgrade to versions 2.5.301 or 3.1.7 to mitigate this vulnerability and ensure proper depth checks in nested data structures.
Original NVD description (English source)
MessagePack for C# is a MessagePack serializer for C#. Prior to 2.5.301 and 3.1.7, MessagePackReader.TrySkip() recursively descends into nested arrays and maps without incrementing the reader depth or calling the configured depth checks. This bypasses MessagePackSecurity.MaximumObjectGraphDepth, the library's documented protection against deeply nested object graphs. Many generated and dynamic formatters call reader.Skip() when they encounter unknown map keys, unknown array members, ignored fields, or data that should be skipped for forward compatibility. A deeply nested value in one of these skipped positions can therefore cause unbounded recursion and an uncatchable StackOverflowException. This vulnerability is fixed in 2.5.301 and 3.1.7.