CVE-2026-52919
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In the Linux kernel, the batman-adv module's tp_meter counter underflows during shutdown due to multiple callers of batadv_tp_sender_shutdown(). This causes a use-after-free when the interface is removed while a zombie sender thread loops indefinitely.
Risk Assessment
The organization risks system crashes or potential kernel compromise if an attacker triggers a race condition during bandwidth measurement session teardown in batman-adv mesh networks.
Recommendation
Immediately update the Linux kernel to a version containing the fix that uses atomic_xchg() to safely transition the counter from 1 to 0. Check your distribution for the patch and apply it with priority on systems using batman-adv.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: batman-adv: fix tp_meter counter underflow during shutdown batadv_tp_sender_shutdown() unconditionally decrements the "sending" atomic counter. If multiple paths (e.g. timeout, user cancel, and normal finish) call this function, the counter can underflow to -1. Since the sender logic treats any non-zero value as "still sending", a negative value causes the sender kthread to loop indefinitely. This leads to a use-after-free when the interface is removed while the zombie thread is still active. Fix this by using atomic_xchg() to ensure the counter only transitions from 1 to 0 once. [sven: added missing change in batadv_tp_send]