CVE-2026-43197netconsole: avoid OOB reads, msg is not nul-terminated

Official description

In the Linux kernel, the following vulnerability has been resolved: netconsole: avoid OOB reads, msg is not nul-terminated msg passed to netconsole from the console subsystem is not guaranteed to be nul-terminated. Before recent commit 7eab73b18630 ("netconsole: convert to NBCON console infrastructure") the message would be placed in printk_shared_pbufs, a static global buffer, so KASAN had harder time catching OOB accesses. Now we see: printk: console [netcon_ext0] enabled BUG: KASAN: slab-out-of-bounds in string+0x1f7/0x240 Read of size 1 at addr ffff88813b6d4c00 by task pr/netcon_ext0/594 CPU: 65 UID: 0 PID: 594 Comm: pr/netcon_ext0 Not tainted 6.19.0-11754-g4246fd6547c9 Call Trace: kasan_report+0xe4/0x120 string+0x1f7/0x240 vsnprintf+0x655/0xba0 scnprintf+0xba/0x120 netconsole_write+0x3fe/0xa10 nbcon_emit_next_record+0x46e/0x860 nbcon_kthread_func+0x623/0x750 Allocated by task 1: nbcon_alloc+0x1ea/0x450 register_console+0x26b/0xe10 init_netconsole+0xbb0/0xda0 The buggy address belongs to the object at ffff88813b6d4000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 0 bytes to the right of allocated 3072-byte region [ffff88813b6d4000, ffff88813b6d4c00)

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/68fe91df6ea822dae772fceaad0686e4f5839aec
• https://git.kernel.org/stable/c/8fe132c4873f9eb1b86ddbf31216e9d961a0b8b9
• https://git.kernel.org/stable/c/3126a2f98beaec5a554a1fb31c46db1e8542665e
• https://git.kernel.org/stable/c/74ab1456eaa3b2eb986138f9e1f4cb37e73b6f58
• https://git.kernel.org/stable/c/82aec772fca2223bc5774bd9af486fd95766e578