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 — SYSopenat, SYSftruncate, and SYS_pwrite64 — can cause the kernel to hang.
Root cause analysis shows that the size validation code in exfatfind() does not check whether dentry.stream.validsize 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.
{
"cna_assigner": "Linux",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40287.json"
}