CVE-2026-43197: netconsole: avoid OOB reads, msg is not nul-terminated
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 printksharedpbufs, a static global buffer, so KASAN had harder time catching OOB accesses. Now we see:
printk: console [netconext0] enabled BUG: KASAN: slab-out-of-bounds in string+0x1f7/0x240 Read of size 1 at addr ffff88813b6d4c00 by task pr/netconext0/594
CPU: 65 UID: 0 PID: 594 Comm: pr/netconext0 Not tainted 6.19.0-11754-g4246fd6547c9 Call Trace: kasanreport+0xe4/0x120 string+0x1f7/0x240 vsnprintf+0x655/0xba0 scnprintf+0xba/0x120 netconsolewrite+0x3fe/0xa10 nbconemitnextrecord+0x46e/0x860 nbconkthreadfunc+0x623/0x750
Allocated by task 1: nbconalloc+0x1ea/0x450 registerconsole+0x26b/0xe10 initnetconsole+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 Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch 7eab73b18630 - Compensating control
If affected, disable netconsole (console module netcon_ext0 / netconsole) to prevent printk messages from being processed by the netconsole NBCON console infrastructure until the fix is applied.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-43197?
CVE-2026-43197 has been classified as a moderate severity vulnerability due to the potential for out-of-bounds read issues.
How do I fix CVE-2026-43197?
To resolve CVE-2026-43197, update your Linux kernel to the latest version that includes the fix for this vulnerability.
What systems are affected by CVE-2026-43197?
CVE-2026-43197 affects the Linux kernel across various distributions that utilize netconsole.
Can CVE-2026-43197 lead to exploitation?
Yes, CVE-2026-43197 can potentially lead to information disclosure through out-of-bounds reads if not mitigated.
Is there a workaround for CVE-2026-43197?
Currently, the recommended approach is to apply the kernel update as there are no known reliable workarounds for CVE-2026-43197.