CVE-2026-64074 fs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap
A slab out-of-bounds write in the Linux kernel statmount function allows attackers to corrupt memory, potentially leading to code execution or privilege escalation.
- 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-2026-64074?
CVE-2026-64074 is a high-severity memory corruption vulnerability in Linux kernel, published on 19 Jul 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:
fs/statmount: fix slab out-of-bounds write in statmount_mnt_idmap
statmount_mnt_idmap() writes one mapping with seq_printf() and then manually advances seq->count to include the NUL separator.
If seq_printf() overflows, seq_set_overflow() sets seq->count to seq->size. The manual seq->count++ changes this to seq->size + 1. seq_has_overflowed() then no longer detects the overflow. The corrupted count returns to statmount_string(), which later executes:
seq->buf[seq->count++] = '\0';
This causes a 1-byte NULL out-of-bounds write on the dynamically allocated seq buffer.
Fix this by checking for overflow immediately after seq_printf().
Weakness: CWE-787
Which versions are affected by CVE-2026-64074?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-64074?
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-2026-64074 being exploited?
There is no known exploitation of CVE-2026-64074 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-64074, DEBIAN-CVE-2026-64074, GHSA-q6fc-4c58-35pf, UBUNTU-CVE-2026-64074.