CVE-2023-53468: ubifs: Fix memory leak in alloc_wbufs()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-01 · updated 2026-06-17
Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: ubifs: Fix memory leak in alloc_wbufs() kmemleak reported a sequence of memory leaks, and show them as following: unreferenced object 0xffff8881575f8400 (size 1024): comm "mount", pid 19625, jiffies 4297119604 (age 20.383s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff8176cecd>] __kmalloc+0x4d/0x150 [<ffffffffa0406b2b>] ubifs_mount+0x307b/0x7170 [ubifs] [<ffffffff819fa8fd>] legacy_get_tree+0xed/0x1d0 [<ffffffff81936f2d>] vfs_get_tree+0x7d/0x230 [<ffffffff819b2bd4>] path_mount+0xdd4/0x17b0 [<ffffffff819b37aa>] __x64_sys_mount+0x1fa/0x270 [<ffffffff83c14295>] do_syscall_64+0x35/0x80 [<ffffffff83e0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 unreferenced object 0xffff8881798a6e00 (size 512): comm "mount", pid 19677, jiffies 4297121912 (age 37.816s) hex dump (first 32 bytes): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk backtrace: [<ffffffff8176cecd>] __kmalloc+0x4d/0x150 [<ffffffffa0418342>] ubifs_wbuf_init+0x52/0x480 [ubifs] [<ffffffffa0406ca5>] ubifs_mount+0x31f5/0x7170 [ubifs] [<ffffffff819fa8fd>] legacy_get_tree+0xed/0x1d0 [<ffffffff81936f2d>] vfs_get_tree+0x7d/0x230 [<ffffffff819b2bd4>] path_mount+0xdd4/0x17b0 [<ffffffff819b37aa>] __x64_sys_mount+0x1fa/0x270 [<ffffffff83c14295>] do_syscall_64+0x35/0x80 [<ffffffff83e0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 The problem is that the ubifs_wbuf_init() returns an error in the loop which in the alloc_wbufs(), then the wbuf->buf and wbuf->inodes that were successfully alloced before are not freed. Fix it by adding error hanging path in alloc_wbufs() which frees the memory alloced before when ubifs_wbuf_init() returns an error.

Affected products

Linux kernel: from 2.6.27 before 5.4.235; from 5.5 before 5.10.173; from 5.11 before 5.15.100; from 5.16 before 6.1.18; from 6.2 before 6.2.5 — fixed in 5.10.173, 5.15.100, 5.4.235, 6.1.18, 6.2.5

How to fix

Upgrade to a fixed version: Linux kernel 5.10.173, 5.15.100, 5.4.235, 6.1.18. Check the vendor advisory for mitigations.

References

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