In the Linux kernel, the following vulnerability has been resolved:

jffs2: fix use-after-free in jffs2_clear_xattr_subsystem

When we mount a jffs2 image, assume that the first few blocks of
the image are normal and contain at least one xattr-related inode,
but the next block is abnormal. As a result, an error is returned
in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then
called in jffs2_build_filesystem() and then again in
jffs2_do_fill_super().

Finally we can observe the following report:
 ==================================================================
 BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac
 Read of size 8 at addr ffff8881243384e0 by task mount/719

 Call Trace:
  dump_stack+0x115/0x16b
  jffs2_clear_xattr_subsystem+0x95/0x6ac
  jffs2_do_fill_super+0x84f/0xc30
  jffs2_fill_super+0x2ea/0x4c0
  mtd_get_sb+0x254/0x400
  mtd_get_sb_by_nr+0x4f/0xd0
  get_tree_mtd+0x498/0x840
  jffs2_get_tree+0x25/0x30
  vfs_get_tree+0x8d/0x2e0
  path_mount+0x50f/0x1e50
  do_mount+0x107/0x130
  __se_sys_mount+0x1c5/0x2f0
  __x64_sys_mount+0xc7/0x160
  do_syscall_64+0x45/0x70
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

 Allocated by task 719:
  kasan_save_stack+0x23/0x60
  __kasan_kmalloc.constprop.0+0x10b/0x120
  kasan_slab_alloc+0x12/0x20
  kmem_cache_alloc+0x1c0/0x870
  jffs2_alloc_xattr_ref+0x2f/0xa0
  jffs2_scan_medium.cold+0x3713/0x4794
  jffs2_do_mount_fs.cold+0xa7/0x2253
  jffs2_do_fill_super+0x383/0xc30
  jffs2_fill_super+0x2ea/0x4c0
 [...]

 Freed by task 719:
  kmem_cache_free+0xcc/0x7b0
  jffs2_free_xattr_ref+0x78/0x98
  jffs2_clear_xattr_subsystem+0xa1/0x6ac
  jffs2_do_mount_fs.cold+0x5e6/0x2253
  jffs2_do_fill_super+0x383/0xc30
  jffs2_fill_super+0x2ea/0x4c0
 [...]

 The buggy address belongs to the object at ffff8881243384b8
  which belongs to the cache jffs2_xattr_ref of size 48
 The buggy address is located 40 bytes inside of
  48-byte region [ffff8881243384b8, ffff8881243384e8)
 [...]
 ==================================================================

The triggering of the BUG is shown in the following stack:
-----------------------------------------------------------
jffs2_fill_super
  jffs2_do_fill_super
    jffs2_do_mount_fs
      jffs2_build_filesystem
        jffs2_scan_medium
          jffs2_scan_eraseblock        <--- ERROR
        jffs2_clear_xattr_subsystem    <--- free
    jffs2_clear_xattr_subsystem        <--- free again
-----------------------------------------------------------

An error is returned in jffs2_do_mount_fs(). If the error is returned
by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to
be executed. If the error is returned by jffs2_build_filesystem(), the
jffs2_clear_xattr_subsystem() also does not need to be executed again.
So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root'
to fix this UAF problem.

https://git.kernel.org/stable/c/22327bd7988f21de3a53c1373f3b81542bfe1f44

https://git.kernel.org/stable/c/30bf7244acf32f19cb722c39f7bc1c2a9f300422

https://git.kernel.org/stable/c/3bd2454162ec6bbb5503233c804fce6e4b6dcec5

https://git.kernel.org/stable/c/4c7c44ee1650677fbe89d86edbad9497b7679b5c

https://git.kernel.org/stable/c/7a75740206af5f17e9f3efa384211cba70213da1

https://git.kernel.org/stable/c/7bb7428dd73991bf4b3a7a61b493ca50046c2b13

https://git.kernel.org/stable/c/8c0f024f29e055840a5a89fe23b96ae3f921afed

https://git.kernel.org/stable/c/9150cb625b46f68d524f4cfd491f1aafc23e10a9

https://git.kernel.org/stable/c/c3b07c875fa8f906f932976460fd14798596f101