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Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2024-40910MEDIUM
Linux Linux — ax25: Fix refcount imbalance on inbound connections
  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  N  N  H    5.5   .0045   37.3     —
AFFECTED
  Product  Versions                                    Fixed
  Linux    9fd75b66b8f68498454d685dc4ba13192ae069b0 –  —
  Linux    5.18 –                                      6.1.95
TIMELINE
  Jul 12  Reserved by Linux
  Jul 12  Published (CNA: Linux)
  Aug 4   RESCORED — CVE-2024-40910 (Linux). CVSS 8.8 → 5.5 (NVD).
CNA: Linux · CVSS v3.1 · 5 references · NVD status: Modified

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().

Lifecycle

Complete event history — 3 events, chronological
DateEventDetail
July 12, 2024ReservedReserved by Linux
July 12, 2024PublishedPublished (CNA: Linux)
August 4, 2026RESCOREDRESCORED — CVE-2024-40910 (Linux). CVSS 8.8 → 5.5 (NVD).

Affected

Affected products and packages — 2 rows
VendorProduct / PackageEcosystemVersion introducedFixed
LinuxLinux9fd75b66b8f68498454d685dc4ba13192ae069b0
LinuxLinux5.186.1.95

References (5)

Related

Authoritative record: CVE-2024-40910 at cve.org

Vendors: linux

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2024-40910 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.