Integer overflow in Msgpack Msgpack-Java
CVE-2026-90473
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.
Vulnerability class: Integer Overflow
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.
Affected products
Weakness classification (CWE)
References
- disclosure@vulncheck.com (product)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (issue-tracking)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-90473?
- CVE-2026-90473 is a medium-severity vulnerability in Msgpack Msgpack-Java, classified under Integer Overflow or Wraparound. CVSS score: 5.3/10. Published 2026-09-12.
- How severe is CVE-2026-90473?
- Medium severity. CVSS v3 base score is 5.3 out of 10.