CVE-2026-64267

fuse: avoid 32-bit prune notification count wrap

MEDIUM
5.5
CVSS Score
Published: July 25, 2026 at 08:49 AM UTC
Updated: August 17, 2026 at 05:17 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%

Description

In the Linux kernel, the following vulnerability has been resolved: fuse: avoid 32-bit prune notification count wrap FUSE_NOTIFY_PRUNE validates the nodeid payload length with: size - sizeof(outarg) != outarg.count * sizeof(u64) On 32-bit kernels, size_t is also 32 bits, so the daemon-controlled count multiplication can wrap. A prune notification with count 0x20000000 and no nodeid payload passes the check, enters the copy loop, and asks the device copy path to read nodeids that are not present in the userspace write buffer. In QEMU this reaches the fuse_copy_fill() BUG_ON(!err) path. Validate the payload length with array_size() instead. That accepts exactly the same valid messages, but avoids wrapping arithmetic before the copy loop consumes the count.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.18 ≤ v < 6.18.396.18 ≤ v < 7.1.46.18 ≤ v < 7.26.19 ≤ v < 7.1.43f29d59e92a96d843c2ff10ebfed92ac268786586.18
Vendor states this is fixed in 54243797cedf55447b4c5d560e8cd709900061ae (fixed)
Vendor states this is fixed in 6e2d84fdeac05bfd858e84a76353fdb84f23a43e (fixed)
Vendor states this is fixed in c78c4b242299bc581e4987e5c2786c6f4760c516 (fixed)
Vendor states this is fixed in 6.18 (unaffected)
Vendor states this is fixed in 6.18.39 (unaffected)
Vendor states this is fixed in 7.1.4 (unaffected)
Vendor states this is fixed in 7.2 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
NVD-CWE-noinfo

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