CyberSecBulletin
CVE-2024-26625NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2024-26625 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 6b950c712a9a05cdda4aea7fcb2848766576c11b, 64babb17e8150771c58575d8f93a35c5296b499f, d0b5b1f12429df3cd9751ab8b2f53729b77733b7 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 6b950c712a9a05cdda4aea7fcb2848766576c11b or 64babb17e8150771c58575d8f93a35c5296b499f or d0b5b1f12429df3cd9751ab8b2f53729b77733b7 or dbc1b89981f9c5360277071d33d7f04a43ffda4a, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.19.307 or 5.4.269 or 5.10.210 or 5.15.149, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux43815482370c510c569fd18edb57afcb0fa8cab6 up to, but not including, 6b950c712a9a05cdda4aea7fcb2848766576c11b; 43815482370c510c569fd18edb57afcb0fa8cab6 up to, but not including, 64babb17e8150771c58575d8f93a35c5296b499f; 43815482370c510c569fd18edb57afcb0fa8cab6 up to, but not including, d0b5b1f12429df3cd9751ab8b2f53729b77733b7; 43815482370c510c569fd18edb57afcb0fa8cab6 up to, but not including, dbc1b89981f9c5360277071d33d7f04a43ffda4a; 43815482370c510c569fd18edb57afcb0fa8cab6 up to, but not including, 9c333d9891f34cea8af1b229dc754552304c8eee; 43815482370c510c569fd18edb57afcb0fa8cab6 up to, but not including, 3151051b787f7cd7e3329ea0016eb9113c248812; 43815482370c510c569fd18edb57afcb0fa8cab6 up to, but not including, 8e51f084b5716653f19e291ed5f026791d4b3ed4; 43815482370c510c569fd18edb57afcb0fa8cab6 up to, but not including, aa2b2eb3934859904c287bf5434647ba72e14c1c; and 1 more ranges6b950c712a9a05cdda4aea7fcb2848766576c11b, 64babb17e8150771c58575d8f93a35c5296b499f, d0b5b1f12429df3cd9751ab8b2f53729b77733b7, dbc1b89981f9c5360277071d33d7f04a43ffda4a, 9c333d9891f34cea8af1b229dc754552304c8eee, 3151051b787f7cd7e3329ea0016eb9113c248812
LinuxLinux Kernel2.6.35 up to, but not including, 4.19.307; 4.20 up to, but not including, 5.4.269; 5.5 up to, but not including, 5.10.210; 5.11 up to, but not including, 5.15.149; 5.16 up to, but not including, 6.1.77; 6.2 up to, but not including, 6.6.16; 6.7 up to, but not including, 6.7.4; 6.84.19.307, 5.4.269, 5.10.210, 5.15.149, 6.1.77, 6.6.16
DebianDebian Linux10.0Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: llc: call sock_orphan() at release time syzbot reported an interesting trace [1] caused by a stale sk->sk_wq pointer in a closed llc socket. In commit ff7b11aa481f ("net: socket: set sock->sk to NULL after calling proto_ops::release()") Eric Biggers hinted that some protocols are missing a sock_orphan(), we need to perform a full audit. In net-next, I plan to clear sock->sk from sock_orphan() and amend Eric patch to add a warning. [1] BUG: KASAN: slab-use-after-free in list_empty include/linux/list.h:373 [inline] BUG: KASAN: slab-use-after-free in waitqueue_active include/linux/wait.h:127 [inline] BUG: KASAN: slab-use-after-free in sock_def_write_space_wfree net/core/sock.c:3384 [inline] BUG: KASAN: slab-use-after-free in sock_wfree+0x9a8/0x9d0 net/core/sock.c:2468 Read of size 8 at addr ffff88802f4fc880 by task ksoftirqd/1/27 CPU: 1 PID: 27 Comm: ksoftirqd/1 Not tainted 6.8.0-rc1-syzkaller-00049-g6098d87eaf31 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc4/0x620 mm/kasan/report.c:488 kasan_report+0xda/0x110 mm/kasan/report.c:601 list_empty include/linux/list.h:373 [inline] waitqueue_active include/linux/wait.h:127 [inline] sock_def_write_space_wfree net/core/sock.c:3384 [inline] sock_wfree+0x9a8/0x9d0 net/core/sock.c:2468 skb_release_head_state+0xa3/0x2b0 net/core/skbuff.c:1080 skb_release_all net/core/skbuff.c:1092 [inline] napi_consume_skb+0x119/0x2b0 net/core/skbuff.c:1404 e1000_unmap_and_free_tx_resource+0x144/0x200 drivers/net/ethernet/intel/e1000/e1000_main.c:1970 e1000_clean_tx_irq drivers/net/ethernet/intel/e1000/e1000_main.c:3860 [inline] e1000_clean+0x4a1/0x26e0 drivers/net/ethernet/intel/e1000/e1000_main.c:3801 __napi_poll.constprop.0+0xb4/0x540 net/core/dev.c:6576 napi_poll net/core/dev.c:6645 [inline] net_rx_action+0x956/0xe90 net/core/dev.c:6778 __do_softirq+0x21a/0x8de kernel/softirq.c:553 run_ksoftirqd kernel/softirq.c:921 [inline] run_ksoftirqd+0x31/0x60 kernel/softirq.c:913 smpboot_thread_fn+0x660/0xa10 kernel/smpboot.c:164 kthread+0x2c6/0x3a0 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 </TASK> Allocated by task 5167: kasan_save_stack+0x33/0x50 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:314 [inline] __kasan_slab_alloc+0x81/0x90 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3813 [inline] slab_alloc_node mm/slub.c:3860 [inline] kmem_cache_alloc_lru+0x142/0x6f0 mm/slub.c:3879 alloc_inode_sb include/linux/fs.h:3019 [inline] sock_alloc_inode+0x25/0x1c0 net/socket.c:308 alloc_inode+0x5d/0x220 fs/inode.c:260 new_inode_pseudo+0x16/0x80 fs/inode.c:1005 sock_alloc+0x40/0x270 net/socket.c:634 __sock_create+0xbc/0x800 net/socket.c:1535 sock_create net/socket.c:1622 [inline] __sys_socket_create net/socket.c:1659 [inline] __sys_socket+0x14c/0x260 net/socket.c:1706 __do_sys_socket net/socket.c:1720 [inline] __se_sys_socket net/socket.c:1718 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1718 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd3/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Freed by task 0: kasan_save_stack+0x33/0x50 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640 poison_slab_object mm/kasan/common.c:241 [inline] __kasan_slab_free+0x121/0x1b0 mm/kasan/common.c:257 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2121 [inlin ---truncated---

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

Spotted an error? Tell us.