Out-of-bounds read in Linux kernel - CVE-2026-99274
Published: November 8, 2026
Vulnerability identifier: #VU161905
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-99274
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service in the Linux kernel.
The vulnerability exists due to an out-of-bounds read in smb3_fiemap() when processing an empty, truncated allocated-range response from an SMB2 server. A remote attacker can return STATUS_BUFFER_OVERFLOW with OutputCount == 0 in response to FSCTL_QUERY_ALLOCATED_RANGES to trigger a read before a NULL response buffer and a kernel crash when an FS_IOC_FIEMAP ioctl is issued on the mounted share.
Affected software
Linux kernel
How to mitigate CVE-2026-99274
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3