Bug 2507204 (CVE-2026-64467) - CVE-2026-64467 kernel: rust_binder: use a u64 stride when cleaning up the offsets array
Summary: CVE-2026-64467 kernel: rust_binder: use a u64 stride when cleaning up the off...
Keywords:
Status: NEW
Alias: CVE-2026-64467
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-25 10:10 UTC by OSIDB Bzimport
Modified: 2026-07-29 09:51 UTC (History)
2 users (show)

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Description OSIDB Bzimport 2026-07-25 10:10:29 UTC
In the Linux kernel, the following vulnerability has been resolved:

rust_binder: use a u64 stride when cleaning up the offsets array

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!


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