Is CVE-2026-90473 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-90473?

CVE-2026-90473 has a CVSS v3 severity of MEDIUM (5.3).

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CVE-2026-90473

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.