CVE-2023-53260
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-15

Last updated on: 2025-12-02

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ovl: fix null pointer dereference in ovl_permission() Following process: P1 P2 path_lookupat link_path_walk inode_permission ovl_permission ovl_i_path_real(inode, &realpath) path->dentry = ovl_i_dentry_upper(inode) drop_cache __dentry_kill(ovl_dentry) iput(ovl_inode) ovl_destroy_inode(ovl_inode) dput(oi->__upperdentry) dentry_kill(upperdentry) dentry_unlink_inode upperdentry->d_inode = NULL realinode = d_inode(realpath.dentry) // return NULL inode_permission(realinode) inode->i_sb // NULL pointer dereference , will trigger an null pointer dereference at realinode: [ 335.664979] BUG: kernel NULL pointer dereference, address: 0000000000000002 [ 335.668032] CPU: 0 PID: 2592 Comm: ls Not tainted 6.3.0 [ 335.669956] RIP: 0010:inode_permission+0x33/0x2c0 [ 335.678939] Call Trace: [ 335.679165] <TASK> [ 335.679371] ovl_permission+0xde/0x320 [ 335.679723] inode_permission+0x15e/0x2c0 [ 335.680090] link_path_walk+0x115/0x550 [ 335.680771] path_lookupat.isra.0+0xb2/0x200 [ 335.681170] filename_lookup+0xda/0x240 [ 335.681922] vfs_statx+0xa6/0x1f0 [ 335.682233] vfs_fstatat+0x7b/0xb0 Fetch a reproducer in [Link]. Use the helper ovl_i_path_realinode() to get realinode and then do non-nullptr checking.
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Meta Information
Published
2025-09-15
Last Modified
2025-12-02
Generated
2026-06-16
AI Q&A
2025-09-15
EPSS Evaluated
2026-06-15
NVD
CVE-2023-53260
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 5.19 (inc) to 6.1.43 (exc)
linux linux_kernel From 6.2 (inc) to 6.4.4 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.
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Executive Summary

This vulnerability is a null pointer dereference in the Linux kernel's overlay filesystem (ovl) permission checking function ovl_permission(). It occurs when the function ovl_i_path_real() returns a real path with a dentry whose inode pointer is NULL, leading to a NULL pointer dereference in inode_permission(). This can cause the kernel to crash (BUG) due to accessing a NULL pointer.

Impact Analysis

This vulnerability can cause a kernel crash (NULL pointer dereference), potentially leading to a denial of service (DoS) condition on affected Linux systems using the overlay filesystem. This could disrupt system availability or stability.

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