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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
msgpack msgpack-java unaffected
Version Status Constraints
0 affected ≤ 0.9.12

No data.

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Project Subscriptions

Vendors Products
Msgpack Subscribe
Messagepack Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/msgpack/msgpack-java cve-icon cve-icon
https://github.com/msgpack/msgpack-java/blob/v0.9.12/msgpack-core/src/main/java/org/msgpack/core/MessageUnpacker.java#L573-L581 cve-icon cve-icon
https://github.com/msgpack/msgpack-java/issues/1014 cve-icon cve-icon
https://www.vulncheck.com/advisories/msgpack-java-through-0.9.12-integer-overflow-via-map32 cve-icon cve-icon
History

Sat, 12 Sep 2026 11:15:00 +0000

Type Values Removed Values Added
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.
Title msgpack-java through 0.9.12 Integer Overflow via MAP32
First Time appeared Msgpack
Msgpack messagepack
Weaknesses CWE-190
CPEs cpe:2.3:a:msgpack:messagepack:*:*:*:*:*:java:*:*
Vendors & Products Msgpack
Msgpack messagepack
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-12T11:06:12.224Z

Reserved: 2026-09-12T02:03:27.571Z

Link: CVE-2026-90473

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-12T11:16:34.347

Modified: 2026-09-12T11:16:34.347

Link: CVE-2026-90473

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses