CVE-2026-63126
HighCVSS 7.5Summary
Wire (gRPC/protobuf for Android, Kotlin, Swift, and Java) before 6.4.5 and 7.0.0-alpha04 does not consistently validate attacker-controlled lengths against the current logical message boundary. In Kotlin, decoding paths (e.g., ProtoAdapter.decode, internalNextLengthDelimited, ReadBuffer.readVarint, ProtoDecoder.decodeSizeDelimited) can cross logical boundaries, perform pointer arithmetic, or reserve excessive memory. An attacker supplying malformed protobuf bytes can cause unchecked exceptions, traps, out-of-bounds behavior, or excessive allocation, resulting in denial of service.
Risk Assessment
The vulnerability allows remote denial of service (DoS) in applications using Wire to parse untrusted protobuf data. No confidentiality, integrity, or code-execution impact is known, but service availability may be disrupted.
Recommendation
Upgrade the Wire library to version 6.4.5 or 7.0.0-alpha04 (or later). Until patched, avoid processing untrusted protobuf data through the vulnerable decoding paths.
Other vulnerabilities in Wire
See all- CVE-2026-61695High
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.
- CVE-2026-45799High
Vulnerability in Wire library (gRPC/protobuf) for Android, Kotlin, Swift, and Java. In versions prior to 6.3.0 and 7.0.0-alpha03, skipGroup() methods do not validate that LENGTH_DELIMITED field length is non-negative, potentially causing ArrayIndexOutOfBoundsException and crashing services decoding untrusted data.
Original NVD description (English source)
Wire provides gRPC and protocol buffers for Android, Kotlin, Swift, and Java. Prior to 6.4.5 and 7.0.0-alpha04, Wire protobuf readers do not consistently validate attacker-controlled lengths against the current logical message boundary before advancing cursors, pointers, limits, slices, or allocations. In Kotlin, ProtoAdapter.decode(ByteArray) and ProtoAdapter.decode(ByteString) use ByteArrayProtoReader32.internalNextLengthDelimited(), where a positive oversized length can wrap pos + length to a negative limit and escape the existing negative-length check. Related ProtoReader, ReadBuffer.readVarint(), ReadBuffer.verifyAdditional(count:), packed-repeated, nested-message, and ProtoDecoder.decodeSizeDelimited(_:from:) paths can cross logical boundaries, perform pointer arithmetic, reserve capacity, or convert an unrepresentable size before proving the requested bytes exist. An attacker who supplies malformed protobuf bytes can cause unchecked exceptions, traps, out-of-bounds behavior, or excessive allocation, resulting in denial of service without known confidentiality, integrity, or code-execution impact. This issue is fixed in versions 6.4.5 and 7.0.0-alpha04.