Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Messagepack | Messagepack | < 2.5.301 |
Related Weaknesses (CWE)
References
- https://github.com/MessagePack-CSharp/MessagePack-CSharp/security/advisories/GHSMitigationVendor Advisory
FAQ
What is CVE-2026-48506?
CVE-2026-48506 is a vulnerability with a CVSS score of 7.5 (HIGH). 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...
How severe is CVE-2026-48506?
CVE-2026-48506 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-48506?
Check the references section above for vendor advisories and patch information. Affected products include: Messagepack Messagepack.