CVE-2026-23474 mtd: Avoid boot crash in RedBoot partition table parser
A buffer overflow in the Linux kernel's RedBoot partition parser causes a boot crash when specific compiler fortification settings are enabled.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23474?
CVE-2026-23474 is a medium-severity memory corruption vulnerability in Linux kernel, published on 3 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
mtd: Avoid boot crash in RedBoot partition table parser
Given CONFIG_FORTIFY_SOURCE=y and a recent compiler, commit 439a1bcac648 ("fortify: Use __builtin_dynamic_object_size() when available") produces the warning below and an oops.
Searching for RedBoot partition table in 50000000.flash at offset 0x7e0000 ------------[ cut here ]------------ WARNING: lib/string_helpers.c:1035 at 0xc029e04c, CPU#0: swapper/0/1 memcmp: detected buffer overflow: 15 byte read of buffer size 14 Modules linked in: CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.19.0 #1 NONE
As Kees said, "'names' is pointing to the final 'namelen' many bytes of the allocation ... 'namelen' could be basically any length at all. This fortify warning looks legit to me -- this code used to be reading beyond the end of the allocation."
Since the size of the dynamic allocation is calculated with strlen() we can use strcmp() instead of memcmp() and remain within bounds.
Which versions are affected by CVE-2026-23474?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-23474?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-23474 being exploited?
There is no known exploitation of CVE-2026-23474 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-23474, DEBIAN-CVE-2026-23474, GHSA-hvxh-97j9-4hcx, ROOT-OS-DEBIAN-11-CVE-2026-23474, ROOT-OS-DEBIAN-12-CVE-2026-23474, ROOT-OS-DEBIAN-13-CVE-2026-23474 and 3 more.