CVE-2026-44375: Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack...

Description

Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the reader to allocate an attacker-controlled number of bytes on the stack. This can trigger a StackOverflowException, which is not catchable by user code and terminates the process. This vulnerability is fixed in 1.1.62.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.36%

27.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-789

References

Timeline

Published: May 14, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-44375?

Nerdbank.MessagePack is a NativeAOT-compatible MessagePack serialization library. Prior to 1.1.62, Nerdbank.MessagePack contains an uncontrolled stack allocation vulnerability in DateTime decoding. A malicious MessagePack payload can declare an oversized timestamp extension length, causing the reader to allocate an attacker-controlled number of bytes on the stack. This can trigger a StackOverflowException, which is not catchable by user code and terminates the process. This vulnerability is fixed in 1.1.62.

How severe is CVE-2026-44375?

CVE-2026-44375 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.36% probability of exploitation in the next 30 days.

How do I fix CVE-2026-44375?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.