# CVE-2026-90473

## Summary

- **CVE ID:** CVE-2026-90473
- **Severity:** MEDIUM
- **CVSS Score:** 6.9 (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)
- **CWE:** CWE-190
- **Published:** Sep 12, 2026
- **Last Modified:** Sep 12, 2026

## 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.

## Affected Products

- msgpack — msgpack-java (0)

## References

- [CNA](https://github.com/msgpack/msgpack-java/issues/1014)
- [CNA](https://github.com/msgpack/msgpack-java/blob/v0.9.12/msgpack-core/src/main/java/org/msgpack/core/MessageUnpacker.java#L573-L581)
- [CNA](https://github.com/msgpack/msgpack-java)
- [CNA](https://www.vulncheck.com/advisories/msgpack-java-through-0.9.12-integer-overflow-via-map32)

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-12._