CVE-2025-21879: btrfs: fix use-after-free on inode when scanning root during em shrinking
First published: Thu Mar 27 2025(Updated: )
In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free on inode when scanning root during em shrinking At btrfs_scan_root() we are accessing the inode's root (and fs_info) in a call to btrfs_fs_closing() after we have scheduled the inode for a delayed iput, and that can result in a use-after-free on the inode in case the cleaner kthread does the iput before we dereference the inode in the call to btrfs_fs_closing(). Fix this by using the fs_info stored already in a local variable instead of doing inode->root->fs_info.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | ||
| Linux Kernel | >=6.13<6.13.6 | |
| Linux Kernel | =6.14-rc1 | |
| Linux Kernel | =6.14-rc2 | |
| Linux Kernel | =6.14-rc3 | |
| Linux Kernel | =6.14-rc4 |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2025-21879?
CVE-2025-21879 has not been assigned a specific CVSS score yet, but it is considered a critical vulnerability due to the potential for a use-after-free condition.
How do I fix CVE-2025-21879?
To fix CVE-2025-21879, upgrade to a patched version of the Linux kernel that addresses this vulnerability.
What versions of Linux Kernel are affected by CVE-2025-21879?
CVE-2025-21879 affects Linux Kernel versions from 6.13 up to 6.14-rc4.
What are the symptoms of CVE-2025-21879 exploitation?
Exploitation of CVE-2025-21879 may lead to system instability, crashes, or unauthorized access due to the use-after-free error.
Is there a workaround for CVE-2025-21879?
There is no known workaround for CVE-2025-21879; upgrading the kernel is the recommended solution.
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