Executive brief
A vulnerability in the Linux kernel's networking tool interface could allow a local user to cause a system crash or potentially gain unauthorized access. The issue occurs when network device statistics change while they are being queried, leading to a memory error. This affects systems using specific network drivers that support dynamic hardware counters.
Technical details
A race condition exists in the ethtool ioctl interface (net/ethtool/ioctl.c) during statistics retrieval. The process involves three separate ioctl calls: ETHTOOL_GSSET_INFO, ETHTOOL_GSTRINGS, and ETHTOOL_GSTATS. Because the RTNL lock is released between these calls, a device reconfiguration can change the number of available statistics. If the count increases after the userspace buffer has been allocated based on the first call, subsequent calls to ethtool_get_strings() or ethtool_get_stats() can result in a buffer overflow. The fix introduces a check to ensure the userspace buffer size matches the current kernel statistics count, returning zero stats if a mismatch is detected to prevent memory corruption.
Affected products
- Linux Linux Kernel 2.6.12-rc2 to 6.12.x
Timeline
- 2025-12-08: disclosed: Initial patch submission by Gal Pressman
- 2026-01-13: advisory: CVE published
- 2026-01-19: patched: Patch committed to stable tree
References
- https://git.kernel.org/stable/c/3df375a1e75483b7d973c3cc2e46aa374db8428b
- https://git.kernel.org/stable/c/4066b5b546293f44cd6d0e84ece6e3ee7ff27093
- https://git.kernel.org/stable/c/4afcb985355210e1688560dc47e64b94dad35d71
- https://git.kernel.org/stable/c/7b07be1ff1cb6c49869910518650e8d0abc7d25f
- https://git.kernel.org/stable/c/7bea09f60f2ad5d232e2db8f1c14e850fd3fd416
- https://git.kernel.org/stable/c/ca9983bc3a1189bd72f9ae449d925a66b2616326
- https://git.kernel.org/stable/c/f9dc0f45d2cd0189ce666288a29d2cc32c2e44d5