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.

References

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