---
id: CVE-2026-90473
title: >-
  msgpack-java through 0.9.12 contains an integer overflow vulnerability in
  MessageUnpacker.skipValue() when processing MAP32 containers with large
  element counts
summary: >-
  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 wrap…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-190
vendor: msgpack
product: msgpack-java
affected:
  - msgpack-java <= 0.9.12
published: '2026-09-12'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T17:17:47.370'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90473'
references:
  - url: 'https://github.com/msgpack/msgpack-java'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/msgpack/msgpack-java/blob/v0.9.12/msgpack-core/src/main/java/org/msgpack/core/MessageUnpacker.java#L573-L581
    label: disclosure@vulncheck.com
  - url: 'https://github.com/msgpack/msgpack-java/issues/1014'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/msgpack-java-through-0.9.12-integer-overflow-via-map32
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
epss: 0.00412
epssPercentile: 0.32626
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-21T16:04:17.294461Z'
ingestedAt: '2026-09-14T15:23:07.480Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.