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CVE-2025-40287

UnknownEPSS 0.17%

Last modified

CVE-2025-40287 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop bug in the exFAT file system that can lead to a Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is malformed, the following system calls — SYS_openat, SYS_ftruncate, and SYS_pwrite64 — can cause the kernel to hang. Root cause analysis shows that the size validation code in exfat_find() does not check whether dentry.stream.valid_size is negative. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop bug in the exFAT file system that can lead to a Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is malformed, the following system calls — SYS_openat, SYS_ftruncate, and SYS_pwrite64 — can cause the kernel to hang. Root cause analysis shows that the size validation code in exfat_find() does not check whether dentry.stream.valid_size is negative. As a result, the system calls mentioned above can succeed and eventually trigger the DoS issue. This patch adds a check for negative dentry.stream.valid_size to prevent this vulnerability.

Metrics

EPSS Probability
0.17%

6.5th percentile

Probability of exploitation in the next 30 days. Learn more

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2025-40287?
In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop bug in the exFAT file system that can lead to a Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is malformed, the following system calls — SYS_openat, SYS_ftruncate, and SYS_pwrite64 — can cause the kernel to hang. Root cause analysis shows that the size validation code in exfat_find() does not check whether dentry.stream.valid_size is negative. As a result, the system calls mentioned above can succeed and eventually trigger the DoS issue. This patch adds a check for negative dentry.stream.valid_size to prevent this vulnerability.
How severe is CVE-2025-40287?
Severity scoring for CVE-2025-40287 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2025-40287?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-40287?

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Source: NVD / NIST