Skip to main content

Boteraser | Website and Server Security Solutions

🛡️ CVE-2023-52564 — kernel

🟡 CVSS 5.5 — Medium ✅ No Known Exploit NVD
5.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Revert "tty: n_gsm: fix UAF in gsm_cleanup_mux"

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

Revert "tty: n_gsm: fix UAF in gsm_cleanup_mux"

This reverts commit 9b9c8195f3f0d74a826077fc1c01b9ee74907239.

The commit above is reverted as it did not solve the original issue.

gsm_cleanup_mux() tries to free up the virtual ttys by calling

gsm_dlci_release() for each available DLCI. There, dlci_put() is called to

decrease the reference counter for the DLCI via tty_port_put() which

finally calls gsm_dlci_free(). This already clears the pointer which is

being checked in gsm_cleanup_mux() before calling gsm_dlci_release().

Therefore, it is not necessary to clear this pointer in gsm_cleanup_mux()

as done in the reverted commit. The commit introduces a null pointer

dereference:

<TASK>

? __die+0x1f/0x70

? page_fault_oops+0x156/0x420

? search_exception_tables+0x37/0x50

? fixup_exception+0x21/0x310

? exc_page_fault+0x69/0x150

? asm_exc_page_fault+0x26/0x30

? tty_port_put+0x19/0xa0

gsmtty_cleanup+0x29/0x80 [n_gsm]

release_one_tty+0x37/0xe0

process_one_work+0x1e6/0x3e0

worker_thread+0x4c/0x3d0

? __pfx_worker_thread+0x10/0x10

kthread+0xe1/0x110

? __pfx_kthread+0x10/0x10

ret_from_fork+0x2f/0x50

? __pfx_kthread+0x10/0x10

ret_from_fork_asm+0x1b/0x30

</TASK>

The actual issue is that nothing guards dlci_put() from being called

multiple times while the tty driver was triggered but did not yet finished

calling gsm_dlci_free().

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

CVE-2023-52564 is recorded against 2 packages.

  • kernel (from 6.2.0 up to 6.5.6)
  • linux-kernel

Timeline and source

Published on 2 March 2024 and last revised on 12 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

Other advisories for this package

kernel has other advisories on record. If you are patching this one, these are worth checking on the same host:

CVE-2023-52564 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Medium
CVSS Score 5.5
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2024-03-02
Updated 2026-08-20
Modified 2026-08-12

Affected Packages

Software From version Fixed in
kernel 6.2.0 6.5.6
linux-kernel — —

Similar Threats

Vulnerability Monitoring

Track new vulnerabilities in kernel

CVE-2023-52564 is rated CVSS 5.5 Medium. BotEraser monitors your WordPress installation and notifies you when software you use appears in our vulnerability database.

Set Up Free Alerts →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

Browse related advisories

All advisoriesCVECVE 2023
✓