CVE-2026-64267
fuse: avoid 32-bit prune notification count wrap
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.
INFO
Published Date :
July 25, 2026, 10:17 a.m.
Last Modified :
Aug. 17, 2026, 5:17 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to the latest version.
- Ensure FUSE module is configured securely.
- Review kernel patch notes for related security fixes.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64267.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64267 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64267
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64267 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64267 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': '6e2d84fdeac05bfd858e84a76353fdb84f23a43e', 'versionType': 'git'}, {'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': 'c78c4b242299bc581e4987e5c2786c6f4760c516', 'versionType': 'git'}, {'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': '54243797cedf55447b4c5d560e8cd709900061ae', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev.c', 'fs/fuse/notify.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.18'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.18', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fuse/dev.c', 'fs/fuse/notify.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': '6e2d84fdeac05bfd858e84a76353fdb84f23a43e', 'versionType': 'git'}, {'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': 'c78c4b242299bc581e4987e5c2786c6f4760c516', 'versionType': 'git'}, {'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': '54243797cedf55447b4c5d560e8cd709900061ae', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev.c', 'fs/fuse/notify.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.18'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.18', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fuse/dev.c', 'fs/fuse/notify.c'], 'defaultStatus': 'affected'}] -
Initial Analysis by [email protected]
Aug. 12, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.1.4 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.18 up to (excluding) 6.18.39 Added Reference Type kernel.org: https://git.kernel.org/stable/c/54243797cedf55447b4c5d560e8cd709900061ae Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/6e2d84fdeac05bfd858e84a76353fdb84f23a43e Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/c78c4b242299bc581e4987e5c2786c6f4760c516 Types: Patch -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 25, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': '6e2d84fdeac05bfd858e84a76353fdb84f23a43e', 'versionType': 'git'}, {'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': 'c78c4b242299bc581e4987e5c2786c6f4760c516', 'versionType': 'git'}, {'status': 'affected', 'version': '3f29d59e92a96d843c2ff10ebfed92ac26878658', 'lessThan': '54243797cedf55447b4c5d560e8cd709900061ae', 'versionType': 'git'}], 'programFiles': ['fs/fuse/dev.c', 'fs/fuse/notify.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.18'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.18', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/fuse/dev.c', 'fs/fuse/notify.c'], 'defaultStatus': 'affected'}] Added 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. Added Reference https://git.kernel.org/stable/c/54243797cedf55447b4c5d560e8cd709900061ae Added Reference https://git.kernel.org/stable/c/6e2d84fdeac05bfd858e84a76353fdb84f23a43e Added Reference https://git.kernel.org/stable/c/c78c4b242299bc581e4987e5c2786c6f4760c516