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🛡️ CVE-2023-52486 — kernel

🟠 CVSS 7.8 — High ✅ No Known Exploit NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

drm: Don't unref the same fb many times by mistake due to deadlock handling

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

drm: Don't unref the same fb many times by mistake due to deadlock handling

If we get a deadlock after the fb lookup in drm_mode_page_flip_ioctl()

we proceed to unref the fb and then retry the whole thing from the top.

But we forget to reset the fb pointer back to NULL, and so if we then

get another error during the retry, before the fb lookup, we proceed

the unref the same fb again without having gotten another reference.

The end result is that the fb will (eventually) end up being freed

while it's still in use.

Reset fb to NULL once we've unreffed it to avoid doing it again

until we've done another fb lookup.

This turned out to be pretty easy to hit on a DG2 when doing async

flips (and CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y). The first symptom I

saw that drm_closefb() simply got stuck in a busy loop while walking

the framebuffer list. Fortunately I was able to convince it to oops

instead, and from there it was easier to track down the culprit.

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 high, integrity high, 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:H/I:H/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: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

CVE-2023-52486 is recorded against 2 packages.

  • kernel (from 6.7.0 up to 6.7.3)
  • linux-kernel (from 6.7 up to 6.7.3)

Timeline and source

Published on 29 February 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)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
lists.debian.org (Web)
lists.debian.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-2023-52486 on other distributions

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

Details

Severity High
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2024-02-29
Updated 2026-08-20
Modified 2026-08-12

Affected Packages

Software From version Fixed in
kernel 6.7.0 6.7.3
linux-kernel 6.7 6.7.3

References

Similar Threats

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