Wire: Unauthenticated decoder crash via 32-bit length integer overflow in ByteArrayProtoReader32 (incomplete fix of CVE-2026-45799)
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-63126
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 15:12 UTC · Revision 1
Source evidence
Wire: Unauthenticated decoder crash via 32-bit length integer overflow in ByteArrayProtoReader32 (incomplete fix of CVE-2026-45799)
core-osv · Original sourcePublished 16 Sept 2026, 18:13 UTC
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.
osv:CVE-2026-63126
Complete source record
{
"id": "1423b65383b03d05fb0e4b9988ca2d79bb2a3ba3e974beb14781779fc46e051b",
"url": "https://osv.dev/vulnerability/CVE-2026-63126",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Wire: Unauthenticated decoder crash via 32-bit length integer overflow in ByteArrayProtoReader32 (incomplete fix of CVE-2026-45799)",
"summary": "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.",
"evidence": "osv:CVE-2026-63126",
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"modified": "2026-10-28T02:30:29.728254973Z",
"provider": "osv",
"references": [
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"https://github.com/square/wire/releases/tag/7.0.0-alpha04",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63126.json",
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"source_id": "core-osv",
"document_id": 496708,
"published_at": "2026-09-16T18:13:33.197+00:00"
}