Medium 5.3Published Sep 12, 2026

CVE-2026-90473msgpack-java through 0.9.12 Integer Overflow via MAP32

Updated under an hour ago (2026-10-19 07:23 UTC)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for msgpack-java

Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE): CWE-190
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Sep 24, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

msgpack msgpack-java msgpack:java (from the name)	through 0.9.12	CNA record

References

https://github.com/msgpack/msgpack-java/issues/1014issue-tracking
https://github.com/msgpack/msgpack-java/blob/v0.9.12/msgpack-core/src/main/java/org/msgpack/core/MessageUnpacker.java#L573-L581technical-description
https://github.com/msgpack/msgpack-javaproduct
https://www.vulncheck.com/advisories/msgpack-java-through-0.9.12-integer-overflow-via-map32third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.