USB: gadgetfs: Fix race between mounting and unmounting

Description

In the Linux kernel, the following vulnerability has been resolved: USB: gadgetfs: Fix race between mounting and unmounting The syzbot fuzzer and Gerald Lee have identified a use-after-free bug in the gadgetfs driver, involving processes concurrently mounting and unmounting the gadgetfs filesystem. In particular, gadgetfs_fill_super() can race with gadgetfs_kill_sb(), causing the latter to deallocate the_device while the former is using it. The output from KASAN says, in part: BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline] BUG: KASAN: use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline] BUG: KASAN: use-after-free in __refcount_sub_and_test include/linux/refcount.h:272 [inline] BUG: KASAN: use-after-free in __refcount_dec_and_test include/linux/refcount.h:315 [inline] BUG: KASAN: use-after-free in refcount_dec_and_test include/linux/refcount.h:333 [inline] BUG: KASAN: use-after-free in put_dev drivers/usb/gadget/legacy/inode.c:159 [inline] BUG: KASAN: use-after-free in gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086 Write of size 4 at addr ffff8880276d7840 by task syz-executor126/18689 CPU: 0 PID: 18689 Comm: syz-executor126 Not tainted 6.1.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: <TASK> ... atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:176 [inline] __refcount_sub_and_test include/linux/refcount.h:272 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] put_dev drivers/usb/gadget/legacy/inode.c:159 [inline] gadgetfs_kill_sb+0x33/0x100 drivers/usb/gadget/legacy/inode.c:2086 deactivate_locked_super+0xa7/0xf0 fs/super.c:332 vfs_get_super fs/super.c:1190 [inline] get_tree_single+0xd0/0x160 fs/super.c:1207 vfs_get_tree+0x88/0x270 fs/super.c:1531 vfs_fsconfig_locked fs/fsopen.c:232 [inline] The simplest solution is to ensure that gadgetfs_fill_super() and gadgetfs_kill_sb() are serialized by making them both acquire a new mutex.

Scores

EPSS (exploitation in 30 days)

0.23% · top 86% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.7.

Weakness

• CWE-416 (opens in a new tab)All about CWE-416 and its CVEs

Affected products

• Linux · Linux

  • affected e5d82a7360d124ae1a38c2a5eac92ba49b125191 – < 9a39f4626b361ee7aa10fd990401c37ec3b466ae
  • affected e5d82a7360d124ae1a38c2a5eac92ba49b125191 – < 856e4b5e53f21edbd15d275dde62228dd94fb2b4
  • affected e5d82a7360d124ae1a38c2a5eac92ba49b125191 – < a2e075f40122d8daf587db126c562a67abd69cf9
  • affected e5d82a7360d124ae1a38c2a5eac92ba49b125191 – < 616fd34d017000ecf9097368b13d8a266f4920b3
  • affected e5d82a7360d124ae1a38c2a5eac92ba49b125191 – < d18dcfe9860e842f394e37ba01ca9440ab2178f4

• Linux · Linux

  • affected 5.3
  • unaffected < 5.3
  • unaffected 5.4.230 – ≤ 5.4.*
  • unaffected 5.10.165 – ≤ 5.10.*
  • unaffected 5.15.90 – ≤ 5.15.*
  • unaffected 6.1.8 – ≤ 6.1.*
  • unaffected 6.2 – ≤ *

References (5)

• https://git.kernel.org/stable/c/9a39f4626b361ee7aa10fd990401c37ec3b466ae (opens in a new tab)
• https://git.kernel.org/stable/c/856e4b5e53f21edbd15d275dde62228dd94fb2b4 (opens in a new tab)
• https://git.kernel.org/stable/c/a2e075f40122d8daf587db126c562a67abd69cf9 (opens in a new tab)
• https://git.kernel.org/stable/c/616fd34d017000ecf9097368b13d8a266f4920b3 (opens in a new tab)
• https://git.kernel.org/stable/c/d18dcfe9860e842f394e37ba01ca9440ab2178f4 (opens in a new tab)

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2022-48869](https://trackcve.app/badge/CVE-2022-48869.svg)](https://trackcve.app/cve/CVE-2022-48869)

Record last updated 11 May 2026, 18:48 UTC.