Medium [CVE-2026-74703] Validate T10 PI scatterlist counts
This medium-severity Red Hat Linux advisory covers CVE-2026-74703.
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Summary
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.
When T10 Protection Information (PI) is negotiated, a remote attacker could send a specially crafted request with malformed scatterlist counts. This could lead to an invalid memory allocation operation, triggering a kernel panic and resulting in a Denial of Service (DoS) for the affected system.
Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-191.
Red Hat lists Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9 as not affected.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 53 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 53 minutes ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 53 minutes ago·verify at source
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