fuse: avoid 32-bit prune notification count wrap

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64267
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-25 10:17:06 UTC
Updated2026-07-30 15:00:27 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.001980000 probability, percentile 0.098410000 (date 2026-08-01)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 3f29d59e92a96d843c2ff10ebfed92ac26878658 6e2d84fdeac05bfd858e84a76353fdb84f23a43e git Not specified
CNA Linux Linux affected 3f29d59e92a96d843c2ff10ebfed92ac26878658 c78c4b242299bc581e4987e5c2786c6f4760c516 git Not specified
CNA Linux Linux affected 3f29d59e92a96d843c2ff10ebfed92ac26878658 54243797cedf55447b4c5d560e8cd709900061ae git Not specified
CNA Linux Linux affected 6.18 Not specified
CNA Linux Linux unaffected 6.18 semver Not specified
CNA Linux Linux unaffected 6.18.39 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.4 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/54243797cedf55447b4c5d560e8cd709900061ae 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c78c4b242299bc581e4987e5c2786c6f4760c516 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6e2d84fdeac05bfd858e84a76353fdb84f23a43e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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