Wire Swift runtime: negative LENGTH_DELIMITED length in skipGroup() crashes any protobuf-decoding service
Historical advisory recorded 23 Oct 2026 15:48:27 UTC. Read the latest advisory.
cve-program · CVE-2026-61695
PublishedWire 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.
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CVE-2026-61695 · CVE overview and exploitation status
cve-program · CVE-2026-61695
- https://github.com/square/wire/security/advisories/GHSA-86wm-r4c5-2rc9
- https://github.com/square/wire/pull/3616
- https://github.com/square/wire/commit/24043b6b3a5e5974a978f2745b76d50b31407c1c
- https://github.com/square/wire/commit/81ff7f24a6795d9a8be2e03f272b2d979a5d2c7e
- https://github.com/square/wire/releases/tag/6.4.1
- https://github.com/square/wire/releases/tag/7.0.0-alpha04
This historical advisory does not include today's related changes. Open the latest advisory to find current connections.