CVE-2025-68339

The record

In the Linux kernel, the following vulnerability has been resolved: atm/fore200e: Fix possible data race in fore200e_open() Protect access to fore200e->available_cell_rate with rate_mtx lock in the error handling path of fore200e_open() to prevent a data race. The field fore200e->available_cell_rate is a shared resource used to track available bandwidth. It is concurrently accessed by fore200e_open(), fore200e_close(), and fore200e_change_qos(). In fore200e_open(), the lock rate_mtx is correctly held when subtracting vcc->qos.txtp.max_pcr from available_cell_rate to reserve bandwidth. However, if the subsequent call to fore200e_activate_vcin() fails, the function restores the reserved bandwidth by adding back to available_cell_rate without holding the lock. This introduces a race condition because available_cell_rate is a global device resource shared across all VCCs. If the error path in fore200e_open() executes concurrently with operations like fore200e_close() or fore200e_change_qos() on other VCCs, a read-modify-write race occurs. Specifically, the error path reads the rate without the lock. If another CPU acquires the lock and modifies the rate (e.g., releasing bandwidth in fore200e_close()) between this read and the subsequent write, the error path will overwrite the concurrent update with a stale value. This results in incorrect bandwidth accounting.

Affected packages

Related vulnerabilities

• CVE-2026-23226 In the Linux kernel, the following vulnerability has been resolved: ksmbd: add chann_lock… Also affects Kernel
• CVE-2026-23225 In the Linux kernel, the following vulnerability has been resolved: sched/mmcid: Don't… Also affects Kernel
• CVE-2026-23230 In the Linux kernel, the following vulnerability has been resolved: smb: client: split… Also affects Kernel
• CVE-2026-23224 In the Linux kernel, the following vulnerability has been resolved: erofs: fix UAF issue… Also affects Kernel
• CVE-2026-23227 In the Linux kernel, the following vulnerability has been resolved: drm/exynos: vidi: use… Also affects Kernel
• CVE-2026-23223 In the Linux kernel, the following vulnerability has been resolved: xfs: fix UAF in… Also affects Kernel
• CVE-2026-23228 In the Linux kernel, the following vulnerability has been resolved: smb: server: fix leak… Also affects Kernel
• CVE-2026-23229 In the Linux kernel, the following vulnerability has been resolved: crypto: virtio - Add… Also affects Kernel