Executive brief
A race condition in the Linux kernel's virtual console screen driver can lead to a system crash. This occurs when the system attempts to update a console that has been deallocated during a write operation. An attacker with local access could potentially exploit this to cause a denial-of-service (system crash).
Technical details
A race condition exists in the vcs_write() function of drivers/tty/vt/vc_screen.c. When the console_lock is temporarily dropped to copy data from userspace, the vc_data pointer can become stale if the console is deallocated. Upon re-acquiring the lock, the code may proceed to call vcs_scr_updated() with a NULL pointer, triggering a null pointer dereference in vcs_notifier(). The fix introduces a NULL check for the vc pointer before the notifier call. This is a local attack vector requiring the ability to perform concurrent writes to the virtual console screen.
Affected products
- Linux Linux kernel 8fb9ea65c9d1 to 09a43e81279b8da15526da09877134b8bcf618b0
- Linux Linux kernel 8fb9ea65c9d1 to 43a6281790273c1b0a9ab76609ff0245b968f1e6
- Linux Linux kernel 8fb9ea65c9d1 to 73049768ad57145acd337102c5aa3c788e6642c8
- Linux Linux kernel 8fb9ea65c9d1 to 74be188eb2dc1c99d63986167b9a67d415fe7326
- Linux Linux kernel 8fb9ea65c9d1 to 7cc3dd79777f6ae4625ec37e84dd18a26dc88bde
- Linux Linux kernel 8fb9ea65c9d1 to 8232fca738011ca2ec865b46ec721d1796dc0580
- Linux Linux kernel 8fb9ea65c9d1 to a287620312dc6dcb9a093417a0e589bf30fcf38a
- Linux Linux kernel e3d1adcad5b73c7ed0c7edb35ab68abcaa45cf67 to b6bbb85cf45bf0b070e741997fe0af3a772c5ad5
- Linux Linux kernel 3338d0b9acde770ee588eead5cac32c25e7048fc to ff4806202749a51938236214adc0281481a57366
Timeline
- 2026-06-04: other: Patch authored
- 2026-07-19: advisory: CVE published
References
- https://git.kernel.org/stable/c/09a43e81279b8da15526da09877134b8bcf618b0
- https://git.kernel.org/stable/c/43a6281790273c1b0a9ab76609ff0245b968f1e6
- https://git.kernel.org/stable/c/73049768ad57145acd337102c5aa3c788e6642c8
- https://git.kernel.org/stable/c/74be188eb2dc1c99d63986167b9a67d415fe7326
- https://git.kernel.org/stable/c/7cc3dd79777f6ae4625ec37e84dd18a26dc88bde
- https://git.kernel.org/stable/c/8232fca738011ca2ec865b46ec721d1796dc0580
- https://git.kernel.org/stable/c/a287620312dc6dcb9a093417a0e589bf30fcf38a