CVE-2024-40910

MEDIUM EPSS 22.4%
Published Jul 12, 20241y ago · Modified Jun 17, 20262w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Jul 12, 2024 1y ago
Last Modified Jun 17, 2026 2w ago

Description

In the Linux kernel, the following vulnerability has been resolved: ax25: Fix refcount imbalance on inbound connections When releasing a socket in ax25_release(), we call netdev_put() to decrease the refcount on the associated ax.25 device. However, the execution path for accepting an incoming connection never calls netdev_hold(). This imbalance leads to refcount errors, and ultimately to kernel crashes. A typical call trace for the above situation will start with one of the following errors: refcount_t: decrement hit 0; leaking memory. refcount_t: underflow; use-after-free. And will then have a trace like: Call Trace: <TASK> ? show_regs+0x64/0x70 ? __warn+0x83/0x120 ? refcount_warn_saturate+0xb2/0x100 ? report_bug+0x158/0x190 ? prb_read_valid+0x20/0x30 ? handle_bug+0x3e/0x70 ? exc_invalid_op+0x1c/0x70 ? asm_exc_invalid_op+0x1f/0x30 ? refcount_warn_saturate+0xb2/0x100 ? refcount_warn_saturate+0xb2/0x100 ax25_release+0x2ad/0x360 __sock_release+0x35/0xa0 sock_close+0x19/0x20 [...] On reboot (or any attempt to remove the interface), the kernel gets stuck in an infinite loop: unregister_netdevice: waiting for ax0 to become free. Usage count = 0 This patch corrects these issues by ensuring that we call netdev_hold() and ax25_dev_hold() for new connections in ax25_accept(). This makes the logic leading to ax25_accept() match the logic for ax25_bind(): in both cases we increment the refcount, which is ultimately decremented in ax25_release().

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
22.4% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 5

VendorProductVersionRange
linuxlinux_kernel*≥5.18  –  <6.1.95
linuxlinux_kernel*≥6.2  –  <6.6.35
linuxlinux_kernel*≥6.7  –  <6.9.6
linuxlinux_kernel6.10any
linuxlinux_kernel6.10any

References 5

  • git.kernel.org https://git.kernel.org/stable/c/3c34fb0bd4a4237592c5ecb5b2e2531900c55774
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/52100fd74ad07b53a4666feafff1cd11436362d3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f4df9d6c8d4e4c818252b0419c2165d66eabd4eb
    Patch
  • lists.debian.org https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/3c34fb0bd4a4237592c5ecb5b2e2531900c55774
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/52100fd74ad07b53a4666feafff1cd11436362d3
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a723a6c8d4831cc8e2c7b0c9f3f0c010d4671964
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/f4df9d6c8d4e4c818252b0419c2165d66eabd4eb
    Patch