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🛡️ CVE-2024-56593 — kernel

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

Description

wifi: brcmfmac: Fix oops due to NULL pointer dereference in brcmf_sdiod_sglist_rw()

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

wifi: brcmfmac: Fix oops due to NULL pointer dereference in brcmf_sdiod_sglist_rw()

This patch fixes a NULL pointer dereference bug in brcmfmac that occurs

when a high 'sd_sgentry_align' value applies (e.g. 512) and a lot of queued SKBs

are sent from the pkt queue.

The problem is the number of entries in the pre-allocated sgtable, it is

nents = max(rxglom_size, txglom_size) + max(rxglom_size, txglom_size) >> 4 + 1.

Given the default [rt]xglom_size=32 it's actually 35 which is too small.

Worst case, the pkt queue can end up with 64 SKBs. This occurs when a new SKB

is added for each original SKB if tailroom isn't enough to hold tail_pad.

At least one sg entry is needed for each SKB. So, eventually the "skb_queue_walk loop"

in brcmf_sdiod_sglist_rw may run out of sg entries. This makes sg_next return

NULL and this causes the oops.

The patch sets nents to max(rxglom_size, txglom_size) * 2 to be able handle

the worst-case.

Btw. this requires only 64-35=29 * 16 (or 20 if CONFIG_NEED_SG_DMA_LENGTH) = 464

additional bytes of memory.

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-2024-56593 is recorded against 2 packages.

  • kernel (from 6.7.0 up to 6.12.5)
  • linux-kernel (from 6.7 up to 6.12.5)

Timeline and source

Published on 27 December 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)
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-2024-56593 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 2024-12-27
Updated 2026-08-20
Modified 2026-08-12

Affected Packages

Software From version Fixed in
kernel 6.7.0 6.12.5
linux-kernel 6.7 6.12.5

References

Similar Threats

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