CVE-2026-63126
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of service disruption.
- Exploit odds
- 0.8% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.8% in the next 30 days (EPSS).
- Severity: 7.5 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.8% · EPSS, next 30 days
- Weakness
- CWE-190 · Integer overflow
- Record status
- Awaiting Analysis
Attack profile CVSS 3.1 · 7.5
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-63126.md and follow it. Check whether this project is affected by CVE-2026-63126. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/square/wire/commit/082d5d83cec57ef68f1dd7d3e3d1d641c1fb670f
- https://github.com/square/wire/commit/25ebcabb9ab7f12d1d77af75ecbc51726fddc015
- https://github.com/square/wire/pull/3635
- 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/security/advisories/GHSA-9rm7-3qhh-h2mc
- https://github.com/square/wire/security/advisories/GHSA-9rm7-3qhh-h2mc
References
- https://github.com/square/wire/commit/082d5d83cec57ef68f1dd7d3e3d1d641c1fb670f
- https://github.com/square/wire/commit/25ebcabb9ab7f12d1d77af75ecbc51726fddc015
- https://github.com/square/wire/pull/3635
- 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/security/advisories/GHSA-9rm7-3qhh-h2mc
- https://github.com/square/wire/security/advisories/GHSA-9rm7-3qhh-h2mc