CVE-2026-23121
Published: February 14, 2026· Updated: Feb 18, 2026
Official Description
In the Linux kernel, the following vulnerability has been resolved:
mISDN: annotate data-race around dev->work
dev->work can re read locklessly in mISDN_read()
and mISDN_poll(). Add READ_ONCE()/WRITE_ONCE() annotations.
BUG: KCSAN: data-race in mISDN_ioctl / mISDN_read
write to 0xffff88812d848280 of 4 bytes by task 10864 on cpu 1:
misdn_add_timer drivers/isdn/mISDN/timerdev.c:175 [inline]
mISDN_ioctl+0x2fb/0x550 drivers/isdn/mISDN/timerdev.c:233
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
read to 0xffff88812d848280 of 4 bytes by task 10857 on cpu 0:
mISDN_read+0x1f2/0x470 drivers/isdn/mISDN/timerdev.c:112
do_loop_readv_writev fs/read_write.c:847 [inline]
vfs_readv+0x3fb/0x690 fs/read_write.c:1020
do_readv+0xe7/0x210 fs/read_write.c:1080
__do_sys_readv fs/read_write.c:1165 [inline]
__se_sys_readv fs/read_write.c:1162 [inline]
__x64_sys_readv+0x45/0x50 fs/read_write.c:1162
x64_sys_call+0x2831/0x3000 arch/x86/include/generated/asm/syscalls_64.h:20
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
value changed: 0x00000000 -> 0x00000001
Technical Analysis
CVE-2026-23121 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
Affected Vendors & Products
Exploit & PoC Resources
All References (7)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-23121 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts