CVE-2026-74703 vhost-scsi: Validate T10 PI scatterlist counts
A malformed vhost-scsi request with invalid T10 PI protection bytes can trigger a kernel BUG_ON, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74703?
CVE-2026-74703 is a high-severity denial of service vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
vhost-scsi: Validate T10 PI scatterlist counts
When T10 PI is negotiated, vhost-scsi splits protection bytes from the data iterator before mapping the request scatterlists. A malformed request can claim protection bytes that cover or exceed the full payload length. The former leaves no data bytes to map, while the latter underflows exp_data_len before advancing the iterator. Both cases can let a zero data SGL count reach sg_alloc_table_chained(), which triggers BUG_ON(!nents).
Reject protection lengths that cover or exceed the payload before subtracting prot_bytes and advancing the iterator. Also propagate negative errors from the protection SGL calculation before calling the allocator, matching the data SGL path.
Which versions are affected by CVE-2026-74703?
How do I fix CVE-2026-74703?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-74703 being exploited?
There is no known exploitation of CVE-2026-74703 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74703, DEBIAN-CVE-2026-74703, GHSA-j7pf-235f-jcqv, UBUNTU-CVE-2026-74703.