Linux: Integer Underflow (Wrap or Wraparound)
CVE-2026-64467 is a high-severity integer underflow (wrap or wraparound) vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 89b8cc948dce661af87527623b3a41cdd115e2f9, 74920b1b4e474ba7a4de4323c0458deec49d210b, 803c8a9502e9b97cd6ae937618ef4a8fd6274343 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 89b8cc948dce661af87527623b3a41cdd115e2f9 or 74920b1b4e474ba7a4de4323c0458deec49d210b or 803c8a9502e9b97cd6ae937618ef4a8fd6274343, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.39 or 7.1.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | eafedbc7c050c44744fbdf80bdf3315e860b7513 up to, but not including, 89b8cc948dce661af87527623b3a41cdd115e2f9; eafedbc7c050c44744fbdf80bdf3315e860b7513 up to, but not including, 74920b1b4e474ba7a4de4323c0458deec49d210b; eafedbc7c050c44744fbdf80bdf3315e860b7513 up to, but not including, 803c8a9502e9b97cd6ae937618ef4a8fd6274343; 6.18 | 89b8cc948dce661af87527623b3a41cdd115e2f9, 74920b1b4e474ba7a4de4323c0458deec49d210b, 803c8a9502e9b97cd6ae937618ef4a8fd6274343 |
| Linux | Linux Kernel | 6.18 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.4; 7.2 | 6.18.39, 7.1.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by CNA.
Official description
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!
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Integer Underflow (Wrap or Wraparound)
The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.
More Integer Underflow (Wrap or Wraparound) vulnerabilities (CWE-191)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Integer Underflow (Wrap or Wraparound) vulnerabilities
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 9.3 Critical severity
- 8.8 High severity
- 9.8 Critical severity
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