7.8
HIGH
CVSS 3.1
CVE-2025-40307
exfat: validate cluster allocation bits of the allocation bitmap
Overview
Description
In the Linux kernel, the following vulnerability has been resolved: exfat: validate cluster allocation bits of the allocation bitmap syzbot created an exfat image with cluster bits not set for the allocation bitmap. exfat-fs reads and uses the allocation bitmap without checking this. The problem is that if the start cluster of the allocation bitmap is 6, cluster 6 can be allocated when creating a directory with mkdir. exfat zeros out this cluster in exfat_mkdir, which can delete existing entries. This can reallocate the allocated entries. In addition, the allocation bitmap is also zeroed out, so cluster 6 can be reallocated. This patch adds exfat_test_bitmap_range to validate that clusters used for the allocation bitmap are correctly marked as in-use.
Details
INFO
Published Date :
Dec. 8, 2025, 1:16 a.m.
Last Modified :
Aug. 19, 2026, 5:18 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
Validate allocation bitmap cluster bits to prevent data corruption and reallocation.
- Apply the provided patch to the Linux kernel.
- Update the exfat filesystem driver.
- Ensure cluster allocation bits are validated.
References
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-2025-40307.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-40307 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-2025-40307
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-2025-40307 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-40307 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. 19, 2026
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/87f827d53bd0688597bda63ae95908e2ad39bac0 Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '67ce8034dc0278ddd88cad93d4218a945180dddd', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '6bc58b4c53795ab5fe00648344aa7d9d61175f90', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '79c1587b6cda74deb0c86fc7ba194b92958c793c', 'versionType': 'git'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.7'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.58', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.17.8', 'versionType': 'semver', 'lessThanOrEqual': '6.17.*'}, {'status': 'unaffected', 'version': '6.18', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '87f827d53bd0688597bda63ae95908e2ad39bac0', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '67ce8034dc0278ddd88cad93d4218a945180dddd', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '6bc58b4c53795ab5fe00648344aa7d9d61175f90', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '79c1587b6cda74deb0c86fc7ba194b92958c793c', 'versionType': 'git'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.7'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.1.183', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.58', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.17.8', 'versionType': 'semver', 'lessThanOrEqual': '6.17.*'}, {'status': 'unaffected', 'version': '6.18', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'affected'}] -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 03, 2026
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/67ce8034dc0278ddd88cad93d4218a945180dddd Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '6bc58b4c53795ab5fe00648344aa7d9d61175f90', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '79c1587b6cda74deb0c86fc7ba194b92958c793c', 'versionType': 'git'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.7'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.58', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.17.8', 'versionType': 'semver', 'lessThanOrEqual': '6.17.*'}, {'status': 'unaffected', 'version': '6.18', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '67ce8034dc0278ddd88cad93d4218a945180dddd', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '6bc58b4c53795ab5fe00648344aa7d9d61175f90', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '79c1587b6cda74deb0c86fc7ba194b92958c793c', 'versionType': 'git'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.7'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.6.148', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.58', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.17.8', 'versionType': 'semver', 'lessThanOrEqual': '6.17.*'}, {'status': 'unaffected', 'version': '6.18', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'affected'}] -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 30, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jun. 17, 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': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '6bc58b4c53795ab5fe00648344aa7d9d61175f90', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf', 'versionType': 'git'}, {'status': 'affected', 'version': '1acf1a564b6034b5af1e7fb23cb98cb3bb4f6003', 'lessThan': '79c1587b6cda74deb0c86fc7ba194b92958c793c', 'versionType': 'git'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.7'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.12.58', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.17.8', 'versionType': 'semver', 'lessThanOrEqual': '6.17.*'}, {'status': 'unaffected', 'version': '6.18', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['fs/exfat/balloc.c'], 'defaultStatus': 'affected'}] -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Dec. 08, 2025
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: exfat: validate cluster allocation bits of the allocation bitmap syzbot created an exfat image with cluster bits not set for the allocation bitmap. exfat-fs reads and uses the allocation bitmap without checking this. The problem is that if the start cluster of the allocation bitmap is 6, cluster 6 can be allocated when creating a directory with mkdir. exfat zeros out this cluster in exfat_mkdir, which can delete existing entries. This can reallocate the allocated entries. In addition, the allocation bitmap is also zeroed out, so cluster 6 can be reallocated. This patch adds exfat_test_bitmap_range to validate that clusters used for the allocation bitmap are correctly marked as in-use. Added Reference https://git.kernel.org/stable/c/13c1d24803d5b0446b3f6f0fdd67e07ac1fdc7bf Added Reference https://git.kernel.org/stable/c/6bc58b4c53795ab5fe00648344aa7d9d61175f90 Added Reference https://git.kernel.org/stable/c/79c1587b6cda74deb0c86fc7ba194b92958c793c
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.