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Fencer Vulns
high 7.8

CVE-2023-52572 json

cifs: Fix UAF in cifs_demultiplex_thread()

published 2024-03-02 2 y ago modified 2026-08-05 3 mo ago also EUVD-2023-57196

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

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

cifs: Fix UAF in cifs_demultiplex_thread()

There is a UAF when xfstests on cifs:

BUG: KASAN: use-after-free in smb2_is_network_name_deleted+0x27/0x160 Read of size 4 at addr ffff88810103fc08 by task cifsd/923

CPU: 1 PID: 923 Comm: cifsd Not tainted 6.1.0-rc4+ #45 ... Call Trace: <TASK> dump_stack_lvl+0x34/0x44 print_report+0x171/0x472 kasan_report+0xad/0x130 kasan_check_range+0x145/0x1a0 smb2_is_network_name_deleted+0x27/0x160 cifs_demultiplex_thread.cold+0x172/0x5a4 kthread+0x165/0x1a0 ret_from_fork+0x1f/0x30 </TASK>

Allocated by task 923: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_slab_alloc+0x54/0x60 kmem_cache_alloc+0x147/0x320 mempool_alloc+0xe1/0x260 cifs_small_buf_get+0x24/0x60 allocate_buffers+0xa1/0x1c0 cifs_demultiplex_thread+0x199/0x10d0 kthread+0x165/0x1a0 ret_from_fork+0x1f/0x30

Freed by task 921: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x40 ____kasan_slab_free+0x143/0x1b0 kmem_cache_free+0xe3/0x4d0 cifs_small_buf_release+0x29/0x90 SMB2_negotiate+0x8b7/0x1c60 smb2_negotiate+0x51/0x70 cifs_negotiate_protocol+0xf0/0x160 cifs_get_smb_ses+0x5fa/0x13c0 mount_get_conns+0x7a/0x750 cifs_mount+0x103/0xd00 cifs_smb3_do_mount+0x1dd/0xcb0 smb3_get_tree+0x1d5/0x300 vfs_get_tree+0x41/0xf0 path_mount+0x9b3/0xdd0 __x64_sys_mount+0x190/0x1d0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The UAF is because:

mount(pid: 921) | cifsd(pid: 923) -------------------------------|------------------------------- | cifs_demultiplex_thread SMB2_negotiate | cifs_send_recv | compound_send_recv | smb_send_rqst | wait_for_response | wait_event_state [1] | | standard_receive3 | cifs_handle_standard | handle_mid | mid->resp_buf = buf; [2] | dequeue_mid [3] KILL the process [4] | resp_iov[i].iov_base = buf | free_rsp_buf [5] | | is_network_name_deleted [6] | callback

1. After send request to server, wait the response until mid->mid_state != SUBMITTED; 2. Receive response from server, and set it to mid; 3. Set the mid state to RECEIVED; 4. Kill the process, the mid state already RECEIVED, get 0; 5. Handle and release the negotiate response; 6. UAF.

It can be easily reproduce with add some delay in [3] - [6].

Only sync call has the problem since async call's callback is executed in cifsd process.

Add an extra state to mark the mid state to READY before wakeup the waitter, then it can get the resp safely.

Patch / fix

  • Linux Linux 5.4.297, 5.10.237, 5.15.181, 6.1.56, 6.5.6, 6.6
  • linux Debian 12 6.1.64-1
  • linux Debian 14, Debian 13 6.5.6-1

debian advisories DEBIAN-CVE-2023-52572

  • linux Ubuntu 22.04 LTS 5.15.0-144.157
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1088.95
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1087.96
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1085.91
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1080.83
  • linux-kvm Ubuntu 22.04 LTS 5.15.0-1084.89
  • linux-azure Ubuntu 22.04 LTS 5.15.0-1075.84
  • linux-gkeop Ubuntu 22.04 LTS 5.15.0-1070.78

ubuntu advisories UBUNTU-CVE-2023-52572

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.112.1
  • kernel-source-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.112.1
  • kernel-rt SLE Micro 5.5 5.14.21-150500.13.88.1
  • kernel-source-rt SLE Micro 5.5 5.14.21-150500.13.88.1
  • kernel-64kb SLE High Performance Computing 15 SP5-ESPOS, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS 5.14.21-150500.55.97.1
  • kernel-syms SLE High Performance Computing 15 SP5-ESPOS, SLES for SAP 15 SP5, SLES 15 SP5-LTSS +1 more 5.14.21-150500.55.97.1
  • kernel-source SLE Micro 5.5, SLE High Performance Computing 15 SP5-ESPOS, SLES for SAP 15 SP5 +2 more 5.14.21-150500.55.97.1
  • kernel-default SLE Micro 5.5, SLE High Performance Computing 15 SP5-ESPOS, SLES for SAP 15 SP5 +3 more 5.14.21-150500.55.97.1

suse advisories SUSE-SU-2025:0945-1SUSE-SU-2025:0853-1SUSE-SU-2025:0833-1SUSE-SU-2025:0833-2SUSE-SU-2025:0835-1SUSE-SU-2025:0834-1

  • kernel CBL-Mariner 2.0 5.15.182.1-1

azure linux advisories AZL-54137

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-52572 updated

kernel: cifs: use-after-free in cifs_demultiplex_thread()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.23% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.