CVE-2026-53385

In the Linux kernel, the following vulnerability has been resolved: vc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_write A KASAN null-ptr-deref was observed in vcs_notifier(): BUG: KASAN: null-ptr-deref in vcs_notifier+0x98/0x130 Read of size 2 at addr qmp_cmd_name: qmp_capabilities, arguments: {} The issue is a race condition in vcs_write(). When the console_lock is temporarily dropped (to copy data from userspace), the vc_data pointer obtained from vcs_vc() may become stale. After re-acquiring the lock, vcs_vc() is called again to re-validate the pointer. If the vc has been deallocated in the meantime, vcs_vc() returns NULL, and the while loop breaks (with written > 0). However, after the loop, vcs_scr_updated(vc) is still called with the now-NULL vc pointer, leading to a null pointer dereference in the notifier chain (vcs_notifier dereferences param->vc). Fix this by adding a NULL check for vc before calling vcs_scr_updated().

• linux linux kernel (>= 4.14.327 < 4.15) • linux linux kernel (>= 4.19.284 < 4.20) • linux linux kernel (>= 5.4.244 < 5.5) • linux linux kernel (>= 5.10.181 < 5.10.260) • linux linux kernel (>= 5.15.113 < 5.15.211) • linux linux kernel (>= 6.1.30 < 6.1.177) • linux linux kernel (>= 6.3.4 < 6.4) • linux linux kernel (>= 6.4.1 < 6.6.144) • linux linux kernel (>= 6.7 < 6.12.95) • linux linux kernel (>= 6.13 < 6.18.37) • linux linux kernel (>= 6.19 < 7.0.14) • linux linux kernel (>= 7.1 < 7.1.2) • linux linux kernel 6.4