CVE-2026-53234
Description
In the Linux kernel, the following vulnerability has been resolved:
net: ibm: emac: Fix use-after-free during device removal
The driver was using devm_register_netdev() which causes unregister_netdev()
to be deferred until the devres cleanup phase, which runs after emac_remove()
returns. This creates a use-after-free window where:
1. emac_remove() is called, which tears down hardware (cancels work, detaches
modules, unregisters from MAL)
2. emac_remove() returns
3. devres cleanup runs and finally calls unregister_netdev()
During step 3, the network stack might still process packets, triggering
emac_irq(), emac_poll(), or other handlers that access now-freed hardware
resources (dev->emacp, dev->mal, etc.).
Fix this by replacing devm_register_netdev() with manual register_netdev()
and calling unregister_netdev() at the beginning of emac_remove(), before
any hardware teardown. This ensures the network device is fully stopped and
unregistered before hardware resources are released.
The change is safe because:
- dev->ndev is assigned very early in probe (before any error paths that
could bypass emac_remove)
- platform_set_drvdata() is only called after successful registration, so
emac_remove() only runs for fully registered devices
- unregister_netdev() is idempotent and safe to call on any registered device
Metadata
Severity & Metrics
No CVSS data available.
Affected products (2)
| Vendor | Product | Platform | Versions |
|---|---|---|---|
| Linux | Linux | — | a4dd8535a527061a01f2fd335596fa77ca240a96 < cf8e14db93eaecc4c0c58299be3b3183b0e53ed5, a4dd8535a527061a01f2fd335596fa77ca240a96 < c09c2e236eef6f59e105f38a30f5439e6ccbcad7, a4dd8535a527061a01f2fd335596fa77ca240a96 < c12584cd6078085d707266be864e7e1cc91d74e3, a4dd8535a527061a01f2fd335596fa77ca240a96 < a0130d682222ae21afc395aead7cd2d87e1a8358 |
| Linux | Linux | — | 6.12, 0 < 6.12, 6.12.94 ≤ 6.12.*, 6.18.36 ≤ 6.18.* … |
References (4)