CVE-2026-45799

Received Received - Intake

ByteArrayProtoReader32 Negative Skip in Wire

Publication date: 2026-07-17

Last updated on: 2026-07-17

Assigner: GitHub, Inc.

Description

Wire provides gRPC and protocol buffers for Android, Kotlin, Swift, and Java. Prior to 6.3.0 and 7.0.0-alpha03, ByteArrayProtoReader32.skipGroup() and ProtoReader.skipGroup() in wire-runtime do not validate that a LENGTH_DELIMITED field length is non-negative before skip(), allowing a crafted protobuf varint encoding -128 as a signed Int to make skip(-128) move the internal position negative and make the next readByte() throw ArrayIndexOutOfBoundsException instead of the documented IOException or ProtocolException, which can crash services using ProtoAdapter.decode(byte[]) on untrusted payloads. This issue is fixed in versions 6.3.0 and 7.0.0-alpha03.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-17

Last Modified

2026-07-17

Generated

2026-07-18

AI Q&A

2026-07-18

EPSS Evaluated

N/A

NVD

CVE-2026-45799

Affected Vendors & Products

Vendor	Product	Version / Range
wire	wire-runtime	to 7.0.0-alpha03 (exc)
square	wire	6.3.0
square	wire	7.0.0-alpha03
square	wire	to 6.3.0 (exc)
square	wire	to 7.0.0-alpha03 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-129	The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

Attack-Flow Graph

Executive Summary

This vulnerability involves a missing check for negative-length values in Wire's protobuf group-skipping functions. A crafted payload with a negative length (encoded as -128) causes an internal position counter to underflow, leading to an ArrayIndexOutOfBoundsException instead of proper error handling. This crashes services decoding untrusted payloads.

Detection Guidance

Detecting this vulnerability requires checking the Wire library version in use. Commands like 'find . -name "*.jar" -exec jar tf {} \; | grep -i wire' or 'mvn dependency:tree' in Java projects can help identify the Wire version. If the version is below 6.3.0 or 7.0.0-alpha03, the system is vulnerable.

Impact Analysis

This vulnerability can crash services that decode untrusted protobuf payloads using Wire. It allows denial-of-service attacks by causing unexpected runtime exceptions, potentially disrupting service availability.

Mitigation Strategies

Upgrade the Wire library to version 6.3.0 or later for 6.x branches, or 7.0.0-alpha03 or later for 7.x branches. Avoid decoding untrusted protobuf payloads until the upgrade is complete. Monitor for crashes in services using Wire's protobuf decoding.

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