Linux Kernel up to 6.14.1 fs/quota/dquot.c dquot_writeback_dquots denial of service

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.14.1. Impacted is the function dquot_writeback_dquots of the file fs/quota/dquot.c. Performing a manipulation results in denial of service. This vulnerability is known as CVE-2025-23132. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.14.1. This affects the function dquot_writeback_dquots of the file fs/quota/dquot.c. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: f2fs: quota: fix to avoid warning in dquot_writeback_dquots() F2FS-fs (dm-59): checkpoint=enable has some unwritten data. ------------[ cut here ]------------ WARNING: CPU: 6 PID: 8013 at fs/quota/dquot.c:691 dquot_writeback_dquots+0x2fc/0x308 pc : dquot_writeback_dquots+0x2fc/0x308 lr : f2fs_quota_sync+0xcc/0x1c4 Call trace: dquot_writeback_dquots+0x2fc/0x308 f2fs_quota_sync+0xcc/0x1c4 f2fs_write_checkpoint+0x3d4/0x9b0 f2fs_issue_checkpoint+0x1bc/0x2c0 f2fs_sync_fs+0x54/0x150 f2fs_do_sync_file+0x2f8/0x814 __f2fs_ioctl+0x1960/0x3244 f2fs_ioctl+0x54/0xe0 __arm64_sys_ioctl+0xa8/0xe4 invoke_syscall+0x58/0x114 checkpoint and f2fs_remount may race as below, resulting triggering warning in dquot_writeback_dquots(). atomic write remount - do_remount - down_write(&sb->s_umount); - f2fs_remount - ioctl - f2fs_do_sync_file - f2fs_sync_fs - f2fs_write_checkpoint - block_operations - locked = down_read_trylock(&sbi->sb->s_umount) : fail to lock due to the write lock was held by remount - up_write(&sb->s_umount); - f2fs_quota_sync - dquot_writeback_dquots - WARN_ON_ONCE(!rwsem_is_locked(&sb->s_umount)) : trigger warning because s_umount lock was unlocked by remount If checkpoint comes from mount/umount/remount/freeze/quotactl, caller of checkpoint has already held s_umount lock, calling dquot_writeback_dquots() in the context should be safe. So let's record task to sbi->umount_lock_holder, so that checkpoint can know whether the lock has held in the context or not by checking current w/ it. In addition, in order to not misrepresent caller of checkpoint, we should not allow to trigger async checkpoint for those callers: mount/umount/remount/ freeze/quotactl.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-23132 since 01/11/2025. The exploitability is told to be difficult. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 240657 (Ubuntu 25.04 : Linux kernel vulnerabilities (USN-7594-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.14.2 or 6.15-rc1 eliminates this vulnerability. Applying the patch d7acf0a6c87aa282c86a36dbaa2f92fda88c5884/eb85c2410d6f581e957cd03a644ff6ddbe592af9 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (240657) and CERT Bund (WID-SEC-2025-0844). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel
• Dell Avamar
• SolarWinds Security Event Manager
• Dell NetWorker
• Dell Secure Connect Gateway
• IBM QRadar SIEM

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.14.0
• 6.14.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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