CVE-2026-63816 Details
Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode - ioctl(F2FS_IOC_GARBAGE_COLLECT_RANGE) - shrink - f2fs_gc - gc_data_segment - ra_data_block(cow_inode) - mapping = F2FS_I(inode)->atomic_inode->i_mapping : f2fs_is_cow_file(cow_inode) is true - f2fs_evict_inode(atomic_inode) - clear_inode_flag(fi->cow_inode, FI_COW_FILE) - F2FS_I(fi->cow_inode)->atomic_inode = NULL ... - truncate_inode_pages_final(atomic_inode) - f2fs_grab_cache_folio(mapping) : create folio in atomic_inode->mapping - clear_inode(atomic_inode) - BUG_ON(atomic_inode->i_data.nrpages) We need to add a reference on fi->atomic_inode before using its mapping field during garbage collection, otherwise, it will cause UAF issue.
A use-after-free vulnerability has been identified in the Linux kernel's F2FS (Flash-Friendly File System) implementation. This issue arises in the atomic write handling of F2FS inodes, specifically when the garbage collection process is performed on copy-on-write (COW) files. During this process, the kernel fails to properly manage references to inodes, leading to the potential for accessing freed memory. The vulnerability is triggered when the F2FS garbage collector processes COW files without maintaining a valid reference to the atomic inode, allowing for memory corruption.
Users can upgrade to the latest stable version of the Linux kernel, where this vulnerability has been addressed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
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Weakness Enumeration
No weakness enumeration is available for this CVE.
Affected Products
No affected product data is available for this CVE.
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 17, 2026 | CVE Modified | kernel.org |
| Jul 24, 2026 | CVE Modified | kernel.org |
| Jul 20, 2026 | CVE Modified | kernel.org |
| Jul 19, 2026 | New CVE Received | kernel.org |