In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop… (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.
In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop… (CVE-2025-40287)
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.
Affected software
pkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/[email protected]~14.04.1?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/[email protected]~14.04.1?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=xenialpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=esm-infra-legacy/xenialpkg:deb/ubuntu/[email protected]?arch=source&distro=fips-updates/xenialpkg:deb/ubuntu/[email protected]?arch=source&distro=fips/xenialpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]~18.04.1?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email protected]~18.04.2?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=bionicpkg:deb/ubuntu/[email protected]?arch=source&distro=esm-infra/bionicpkg:deb/ubuntu/[email 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protected]?arch=source&distro=bluefield/noblepkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/[email protected]+fips1?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/[email protected]?arch=source&distro=realtime/noblepkg:deb/ubuntu/[email protected]?arch=source&distro=realtime/noblepkg:deb/ubuntu/[email protected]~24.04.1?arch=source&distro=realtime/noblepkg:deb/ubuntu/[email protected]~24.04.1?arch=source&distro=realtime/noblepkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]?arch=source&distro=questingRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2025-40287
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:14.04:LTS","Ubuntu:Pro:16.04:LTS","Ubuntu:16.04:LTS","Ubuntu:Pro:FIPS:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:18.04:LTS","Ubuntu:Pro:FIPS-updates:18.04:LTS","Ubuntu:Pro:FIPS:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:20.04:LTS","Ubuntu:Pro:FIPS-updates:20.04:LTS","Ubuntu:Pro:FIPS:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:Nvidia-BlueField:22.04:LTS","Ubuntu:Pro:FIPS-preview:22.04:LTS","Ubuntu:Pro:FIPS-updates:22.04:LTS","Ubuntu:Pro:Realtime:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:Nvidia-BlueField:24.04:LTS","Ubuntu:Pro:FIPS-updates:24.04:LTS","Ubuntu:Pro:Realtime:24.04:LTS","Ubuntu:25.10"]
Threat ID: 6a5b64ed2d1edb114c8e8576
Added to database: 07/18/2026, 11:35:09 UTC
Last updated: 09/10/2026, 19:24:56 UTC
Views: 6
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