CVE-2026-98167 smb: client: fix server->total_read for compound encrypted PDUs
A flaw in the Linux kernel SMB client allows out-of-bounds reads via truncated compound encrypted PDUs, potentially leading to information disclosure or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98167?
CVE-2026-98167 is a memory corruption vulnerability in Linux, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix server->total_read for compound encrypted PDUs
In receive_encrypted_standard(), server->total_read is left at the full decrypted frame size when walking sub-PDUs of a compound encrypted frame. As a result, cifs_handle_standard() passes this full size to smb2_check_message(), causing the PDU length guards to incorrectly validate the entire compound frame instead of the current sub-PDU.
This allows truncated non-last sub-PDUs to bypass length validation, leading to out-of-bounds reads in smb2_get_data_area_len().
Fix this by setting server->total_read to the true length of the current sub-PDU: next_cmd for non-last sub-PDUs, and the remaining pdu_length for the last one.
Which versions are affected by CVE-2026-98167?
How do I fix CVE-2026-98167?
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-2026-98167 being exploited?
There is no known exploitation of CVE-2026-98167 in the wild and no public exploit code.
Sources
Also known as AZL-106017, BELL-CVE-2026-98167, DEBIAN-CVE-2026-98167, GHSA-wwfg-4wrm-v6qx, UBUNTU-CVE-2026-98167.