#VU124451 Incorrect Calculation of Buffer Size in Linux kernel - CVE-2026-23380
Published: March 25, 2026
Vulnerability identifier: #VU124451
Vulnerability risk: Low
CVSSv4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-23380
CWE-ID: CWE-131
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerable software:
Linux kernel
Linux kernel
Software vendor:
Linux Foundation
Linux Foundation
Description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper reference counting in the tracing_buffers_mmap_close function when handling memory mappings after a process forks. A local user can trigger a WARN_ON condition by manipulating VMA flags via madvise(MADV_DOFORK), leading to an invalid decrement of the user_mapped reference count and causing a denial of service.
The issue arises when an application removes the VM_DONTCOPY flag using madvise(MADV_DOFORK), allowing the child process to inherit the parent's VMAs without incrementing the reference count.
Remediation
Install security update from vendor's repository.