CVE-2026-61695: Square Wire

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

Wire provides gRPC and protocol buffers for Android, Kotlin, Swift, and Java. Prior to 6.4.1 and 7.0.0-alpha04, Wire's Swift runtime ProtoReader.skipGroup(expectedEndTag:unknownFieldsWriter:) accepts a negative length for a LENGTH_DELIMITED field inside an unknown START_GROUP field. ProtoReader.readData() forwards the negative count to ReadBuffer.readData(count:), whose upper-bound-only check permits the value to reach Foundation Data(bytes:count:) and trigger an unrecoverable process trap instead of a catchable ProtoDecoder.Error. Any Swift process decoding untrusted protobuf bytes can be crashed without authentication, user interaction, or knowledge of the target schema. This issue is fixed in versions 6.4.1 and 7.0.0-alpha04.

Affected products

• Square Wire: before 6.4.1 (fixed in 6.4.1); from 7.0.0-alpha01, before 7.0.0-alpha04 (fixed in 7.0.0-alpha04)

Published 2026-09-23. Last modified 2026-09-30.