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CVE-2026-64467
rust_binder: use a u64 stride when cleaning up the offsets array
Published 2026-07-25 (3 months ago) by the Linux kernel CNA. Subsystem drivers/android. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-64467 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Allocation's Drop walks the offsets array (binder_size_t = u64 entries), cleaning up the objects, but it used usize instead of u64 for both the stride and the per-entry read. On 64-bit kernels (usize == u64) this is harmless, but on 32-bit kernels it walks the 8-byte entries in 4-byte steps, iterating an N-entry array 2N times, and reads the always-zero high word as offset 0, cleaning up the object at offset 0 N extra times. As a result the referenced node or handle ends up with a lower reference count than it actually has (a refcount over-decrement), and binder's reference accounting is corrupted; for example, the owner can be notified of a strong reference release (BR_RELEASE) even though references still remain. Change the stride to u64, and read each entry as a u64, narrowing it to usize with try_into(). On 32-bit ARM, when this over-decrement would drive a count below zero, the driver's existing refcount guard refuses it and fires: rust_binder: Failure: refcount underflow!
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/android/binder/allocation.rs
- What this is
- ANDROID DRIVERSMAINTAINERS section matched on drivers/android/ · linux-kernel@vger.kernel.org · Supported
Show whether Debian builds this, per release
Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.
- bookworm, trixie, forky, sid?
- ?
- not established - no Makefile entry for the affected file
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS
Signals
- Published
- 2026-07-25 (3 months ago)source
- CVSS
- 8.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.17%, higher than 6.3% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/android
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.18 | 6.18.39 | 89b8cc948dce |
| 6.18 | 7.1.4 | 74920b1b4e47 |
| 6.18 | 7.2 | 803c8a9502e9 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The vulnerable path is reached through a local BINDER_WRITE_READ ioctl carrying a crafted Binder transaction.
- AC:LAttack complexity, low
- The attacker controls object zero and the offsets count and can force synchronous cleanup with a later invalid object; no race or uncontrollable condition is required.
- PR:LPrivileges required, low
- An ordinary process permitted to access the Binder device and invoke and transfer objects to the target can trigger the bug; no capability or administrative privilege is required.
- UI:NUser interaction, none
- A malformed later object makes transaction construction fail and invokes cleanup during the attacker's ioctl, without recipient or human action.
- S:CScope, changed
- Prematurely releasing an object owned by a more privileged Binder service can create a user-space use-after-free across the Android application sandbox boundary.
- C:HConfidentiality impact, high
- The attacker can retain a handle after BR_RELEASE frees the owning service's object, then target the stale pointer and potentially obtain code execution and arbitrary access to privileged-process memory.
- I:HIntegrity impact, high
- Exploitation of the resulting stale Binder object can provide attacker-controlled code execution and arbitrary modification within the privileged owning service.
- A:HAvailability impact, high
- Stale-object dispatch can crash a critical Binder service, and the trigger can be repeated to cause persistent service or system disruption.