Integer overflow in square wire
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-190 and the CVSS impact.
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| square | wire | before 6.4.5; 7.0.0-alpha01 to before 7.0.0-alpha04 | 6.4.5, 7.0.0-alpha04 | Patch available | CNA |
| — | com.squareup.wire:wire-runtime (Maven) | before 6.4.5 | 6.4.5 | Patch available | GHSA-9rm7-3qhh-h2mc |
| — | com.squareup.wire:wire-runtime (Maven) | 7.0.0-alpha01 to before 7.0.0-alpha04 | 7.0.0-alpha04 | Patch available | GHSA-9rm7-3qhh-h2mc |
- wire Vendorsquare Affected before 6.4.5; 7.0.0-alpha01 to before 7.0.0-alpha04 Fixed in 6.4.5, 7.0.0-alpha04 Patch available CNA
- com.squareup.wire:wire-runtime (Maven) Vendor— Affected before 6.4.5 Fixed in 6.4.5 Patch available GHSA-9rm7-3qhh-h2mc
- com.squareup.wire:wire-runtime (Maven) Vendor— Affected 7.0.0-alpha01 to before 7.0.0-alpha04 Fixed in 7.0.0-alpha04 Patch available GHSA-9rm7-3qhh-h2mc
Remediation
- Fix · CNA wire (square) Fixed in 6.4.5, 7.0.0-alpha04
- Fix · GHSA-9rm7-3qhh-h2mc com.squareup.wire:wire-runtime (Maven) Fixed in 6.4.5 Advisory →
- Fix · GHSA-9rm7-3qhh-h2mc com.squareup.wire:wire-runtime (Maven) Fixed in 7.0.0-alpha04 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-63126
- 2026-10-03 Alias added: GHSA-9rm7-3qhh-h2mc
References
Other 7
- https://github.com/square/wire/security/advisories/GHSA-9rm7-3qhh-h2mc
- https://github.com/square/wire/pull/3635
- https://github.com/square/wire/commit/082d5d83cec57ef68f1dd7d3e3d1d641c1fb670f
- https://github.com/square/wire/commit/25ebcabb9ab7f12d1d77af75ecbc51726fddc015
- https://github.com/square/wire/releases/tag/6.4.5
- https://github.com/square/wire/releases/tag/7.0.0-alpha04
- https://github.com/square/wire
More square vulnerabilities
- TI-2026-44167 Wire Swift runtime: negative LENGTH_DELIMITED length in skipGroup() crashes any protobuf-decoding service CVSS 3.1HIGH 7.5
- TI-2026-71027 Insecure YAML deserialization in Square Squash symbolication API CVSS 4.0CRITICAL 9.2
- TI-2024-38317 Uncontrolled recursion in square Wire CVSS 3.1MEDIUM 5.8
Sources
- CVE-2026-63126 · CVE Program
- CVE-2026-63126 · NVD
- FIRST EPSS
- GHSA-9rm7-3qhh-h2mc · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences