CVE-2025-40287
NoneCVSS
—
EPSS
0.2%
Published
Dec 6, 2025
CISA due date
—
The record
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.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Linux | Kernel | 0 | 6.12.59 |
| Linux | Kernel | 5.7.0 | 6.12.59 |
| Linux | Kernel | 6.8.0 | 6.12.59 |
| openSUSE:Leap 16.0 | dtb-aarch64 | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-64kb | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-azure | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-default | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-default-base | 0 | 6.12.0-160000.9.1.160000.2.6 |
| openSUSE:Leap 16.0 | kernel-docs | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-kvmsmall | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-obs-build | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-obs-qa | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-rt | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-source | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-syms | 0 | 6.12.0-160000.9.1 |
| openSUSE:Leap 16.0 | kernel-zfcpdump | 0 | 6.12.0-160000.9.1 |
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