CVE-2026-90473

msgpack-java through 0.9.12 Integer Overflow via MAP32

MEDIUM
5.3
CVSS Score
Published: September 12, 2026 at 11:06 AM UTC
Updated: September 23, 2026 at 05:30 PM UTC
2 products affected across 1 vendorMessagepackMsgpack Java

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

msgpack-java through 0.9.12 contains an integer overflow vulnerability in MessageUnpacker.skipValue() when processing MAP32 containers with large element counts. Attackers can supply a MAP32 element count at or above 0x40000000 that wraps when doubled, causing the parser cursor to desynchronize and attacker-controlled data to be returned in place of later fields.

Affected

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

v ≤ 0.9.12
v ≤ 0.9.12

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

5.3MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-190

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