CVE-2022-48668

What it actually does

The vulnerability allows temporary data corruption in SMB3 file operations because the collapse range function does not invalidate the affected cached data regions in the kernel.

Why it matters to the business

Organizations using Linux kernels with SMB3 file sharing may encounter intermittent file data corruption during collapse range operations, leading to data integrity problems in shared file systems until the kernel is updated.

How an attack unfolds

An attacker with the ability to perform or influence file operations on an SMB3-mounted share can trigger collapse range without proper cache discard, causing applications to read stale or corrupted cached data temporarily.

How to fix it

Update affected Linux kernel trees to include commit 49523a4732204bdacbf3941a016503ddb4ddb3b9 or equivalent fixed versions that properly discard cached regions during collapse range.

How to confirm the fix worked

Confirm the running kernel contains the referenced commit hash, re-run xfstest generic/031 to verify no data corruption occurs, and inspect SMB3 cache handling code paths for the fix.

Typical attack path

1. Mount or access an SMB3 share on a vulnerable Linux kernel
2. Trigger file collapse range operations via local processes or SMB clients
3. Read affected file regions before cache is refreshed to observe or exploit corrupted data

How to detect it

Monitor kernel logs and SMB3 file access for unexpected data corruption patterns or cache-related errors on affected systems; no specific post-exploitation artifacts are known.

What your security team should do

• Apply kernel updates containing the fix to all systems using SMB3
• Test file integrity on SMB3 shares after patching
• Review and update custom kernel builds to incorporate the commit