CVE-2026-46195 smb: client: validate dacloffset before building DACL pointers
A malicious SMB server can trigger an integer overflow in the Linux kernel SMB client, leading to potential code execution or denial of service via crafted security descriptors.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46195?
CVE-2026-46195 is a critical vulnerability in Linux kernel, published on 28 May 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: validate dacloffset before building DACL pointers
parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor.
On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths.
Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points.
Which versions are affected by CVE-2026-46195?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46195?
Apply the vendor's patch.
Is CVE-2026-46195 being exploited?
There is no known exploitation of CVE-2026-46195 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-89013, BELL-CVE-2026-46195, DEBIAN-CVE-2026-46195, GHSA-rp7m-xq2f-r4cg, ROOT-OS-DEBIAN-12-CVE-2026-46195, ROOT-OS-UBUNTU-2204-CVE-2026-46195 and 2 more.