What’s Vulnerable › Vulnerabilities

CVE-2026-45799: Wire: skipGroup() missing negative-length check allows 10-byte payload to crash any Wire-decoding service

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-17 · updated 2026-10-24
• Weakness: CWE-129

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.

Affected products

• square wire: before 6.3.0; 7.0.0-alpha01, 7.0.0-alpha02 — fixed in 6.3.0

How to fix

Upgrade to a fixed version: square wire 6.3.0. Check the vendor advisory for mitigations.

References

• https://github.com/square/wire/commit/47d5b0dba53935d5332cd41a80a353b3fc90e7b0
• https://github.com/square/wire/commit/e4e56fab38a547d9625f05c97f1d8f0bcc3a5773
• https://github.com/square/wire/pull/3595
• https://github.com/square/wire/pull/3597
• https://github.com/square/wire/releases/tag/6.3.0
• https://github.com/square/wire/releases/tag/7.0.0-alpha03
• https://github.com/square/wire/security/advisories/GHSA-7xpr-hc2w-34m9
• https://github.com/square/wire/security/advisories/GHSA-7xpr-hc2w-34m9

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