CVE-2026-90473
msgpack-java through 0.9.12 Integer Overflow via MAP32
CVSS Score
5.3
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-190 |
| Vendor | msgpack |
| Product | msgpack-java |
| Published | Sep 12, 2026 |
Stay Ahead of the Next One
Get instant alerts for msgpack msgpack-java
Be the first to know when new medium vulnerabilities affecting msgpack msgpack-java are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None
Affected Versions
msgpack / msgpack-java
0 ≤ 0.9.12
References
github.com: https://github.com/msgpack/msgpack-java/issues/1014 github.com: https://github.com/msgpack/msgpack-java/blob/v0.9.12/msgpack-core/src/main/java/org/msgpack/core/MessageUnpacker.java#L573-L581 github.com: https://github.com/msgpack/msgpack-java vulncheck.com: https://www.vulncheck.com/advisories/msgpack-java-through-0.9.12-integer-overflow-via-map32
Credits
🔍 Wayde Shi (PayPal Cyber Security Team)