---
id: CVE-2026-63126
title: 'Wire provides gRPC and protocol buffers for Android, Kotlin, Swift, and Java'
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 b…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-190
vendor: square
product: wire
affected:
  - wire < 6.4.5
  - 'wire >= 7.0.0-alpha01, < 7.0.0-alpha04'
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T20:17:26.370'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63126'
references:
  - url: >-
      https://github.com/square/wire/commit/082d5d83cec57ef68f1dd7d3e3d1d641c1fb670f
    label: security-advisories@github.com
  - url: >-
      https://github.com/square/wire/commit/25ebcabb9ab7f12d1d77af75ecbc51726fddc015
    label: security-advisories@github.com
  - url: 'https://github.com/square/wire/pull/3635'
    label: security-advisories@github.com
  - url: 'https://github.com/square/wire/releases/tag/6.4.5'
    label: security-advisories@github.com
  - url: 'https://github.com/square/wire/releases/tag/7.0.0-alpha04'
    label: security-advisories@github.com
  - url: 'https://github.com/square/wire/security/advisories/GHSA-9rm7-3qhh-h2mc'
    label: security-advisories@github.com
  - url: 'https://github.com/square/wire/security/advisories/GHSA-9rm7-3qhh-h2mc'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63126'
  - url: 'https://github.com/advisories/GHSA-9rm7-3qhh-h2mc'
tags:
  - nvd
  - cve.org
  - exploit-available
  - ghsa
  - maven
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-16T19:41:27.470490Z'
ingestedAt: '2026-09-16T19:02:30.738Z'
aliases:
  - GHSA-9rm7-3qhh-h2mc
ecosystem: maven
patched:
  - 'com.squareup.wire:wire-runtime 6.4.5'
  - 'com.squareup.wire:wire-runtime 7.0.0-alpha04'
epss: 0.00823
epssPercentile: 0.55457
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-63126)

Affected packages:

- `com.squareup.wire:wire-runtime <= 6.4.4`
- `com.squareup.wire:wire-runtime >= 7.0.0-alpha01, < 7.0.0-alpha04`

Patched in:

- `com.squareup.wire:wire-runtime 6.4.5`
- `com.squareup.wire:wire-runtime 7.0.0-alpha04`

Source: https://github.com/advisories/GHSA-9rm7-3qhh-h2mc