CVE-2026-44375

Nerdbank.MessagePack: Attacker-controlled stackalloc in DateTime decoding causes process-terminating StackOverflowException

HIGH
7.5
CVSS Score
Published: May 14, 2026 at 02:32 PM UTC
Updated: October 26, 2026 at 02:10 PM UTC
1 product affected across 1 vendorNerdbank.MessagePack

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.1.62
Affected range stops below 1.1.62, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-789

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