CyberSecBulletin
CVE-2023-52922NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2023-52922 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 11b8e27ed448baa385d90154a141466bd5e92f18, 9b58d36d0c1ea29a9571e0222a9c29df0ccfb7ff, 9533dbfac0ff7edd77a5fa2c24974b1d66c8b0a6 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 0.3% 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 11b8e27ed448baa385d90154a141466bd5e92f18 or 9b58d36d0c1ea29a9571e0222a9c29df0ccfb7ff or 9533dbfac0ff7edd77a5fa2c24974b1d66c8b0a6 or cf254b4f68e480e73dab055014e002b77aed30ed, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.14.322 or 4.19.291 or 5.4.251 or 5.10.188, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxffd980f976e7fd666c2e61bf8ab35107efd11828 up to, but not including, 11b8e27ed448baa385d90154a141466bd5e92f18; ffd980f976e7fd666c2e61bf8ab35107efd11828 up to, but not including, 9b58d36d0c1ea29a9571e0222a9c29df0ccfb7ff; ffd980f976e7fd666c2e61bf8ab35107efd11828 up to, but not including, 9533dbfac0ff7edd77a5fa2c24974b1d66c8b0a6; ffd980f976e7fd666c2e61bf8ab35107efd11828 up to, but not including, cf254b4f68e480e73dab055014e002b77aed30ed; ffd980f976e7fd666c2e61bf8ab35107efd11828 up to, but not including, 3c3941bb1eb53abe7d640ffee5c4d6b559829ab3; ffd980f976e7fd666c2e61bf8ab35107efd11828 up to, but not including, 995f47d76647708ec26c6e388663ad4f3f264787; ffd980f976e7fd666c2e61bf8ab35107efd11828 up to, but not including, dfd0aa26e9a07f2ce546ccf8304ead6a2914e8a7; ffd980f976e7fd666c2e61bf8ab35107efd11828 up to, but not including, 55c3b96074f3f9b0aee19bf93cd71af7516582bb; and 1 more ranges11b8e27ed448baa385d90154a141466bd5e92f18, 9b58d36d0c1ea29a9571e0222a9c29df0ccfb7ff, 9533dbfac0ff7edd77a5fa2c24974b1d66c8b0a6, cf254b4f68e480e73dab055014e002b77aed30ed, 3c3941bb1eb53abe7d640ffee5c4d6b559829ab3, 995f47d76647708ec26c6e388663ad4f3f264787
LinuxLinux Kernel2.6.25 up to, but not including, 4.14.322; 4.15 up to, but not including, 4.19.291; 4.20 up to, but not including, 5.4.251; 5.5 up to, but not including, 5.10.188; 5.11 up to, but not including, 5.15.123; 5.16 up to, but not including, 6.1.42; 6.2 up to, but not including, 6.4.7; 6.54.14.322, 4.19.291, 5.4.251, 5.10.188, 5.15.123, 6.1.42

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 CISA (ADP).

Official description

In the Linux kernel, the following vulnerability has been resolved: can: bcm: Fix UAF in bcm_proc_show() BUG: KASAN: slab-use-after-free in bcm_proc_show+0x969/0xa80 Read of size 8 at addr ffff888155846230 by task cat/7862 CPU: 1 PID: 7862 Comm: cat Not tainted 6.5.0-rc1-00153-gc8746099c197 #230 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0xd5/0x150 print_report+0xc1/0x5e0 kasan_report+0xba/0xf0 bcm_proc_show+0x969/0xa80 seq_read_iter+0x4f6/0x1260 seq_read+0x165/0x210 proc_reg_read+0x227/0x300 vfs_read+0x1d5/0x8d0 ksys_read+0x11e/0x240 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Allocated by task 7846: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_kmalloc+0x9e/0xa0 bcm_sendmsg+0x264b/0x44e0 sock_sendmsg+0xda/0x180 ____sys_sendmsg+0x735/0x920 ___sys_sendmsg+0x11d/0x1b0 __sys_sendmsg+0xfa/0x1d0 do_syscall_64+0x35/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 7846: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x27/0x40 ____kasan_slab_free+0x161/0x1c0 slab_free_freelist_hook+0x119/0x220 __kmem_cache_free+0xb4/0x2e0 rcu_core+0x809/0x1bd0 bcm_op is freed before procfs entry be removed in bcm_release(), this lead to bcm_proc_show() may read the freed bcm_op.

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: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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