CVE-2026-74356: vhost: fix vhost_get_avail_idx for a non empty ring

mediumCVSS 6.5CVE-2026-74356

CSIRTS triage

vendor: Linux product: Linux kernel Denial of service

What: The vhost device driver returns incorrect available index for non-empty rings, causing guest-host synchronization issues.
Who is affected: Systems running KVM/QEMU with vhost devices (network, block, etc.) and guests using those devices.
Urgency: Medium severity (CVSS 6.5); no known exploitation but ring synchronization faults cause denial of service.
Action: Apply kernel patch that fixes vhost_get_avail_idx calculation for non-empty ring buffers.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 6.5
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74356

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-743560.23% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 14% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-74356	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

highCVE-2026-74356: In the Linux kernel, the following vulnerability has been resolved: vhost: fix vhost_get_avail…nvd

Recent advisories for vhost

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-74713: In the Linux kernel, the following vulnerability has been resolved: vhost_iotlb: bound map all…nvd · 2026-08-22
highCVE-2026-74703: In the Linux kernel, the following vulnerability has been resolved: vhost-scsi: Validate T10 P…nvd · 2026-08-22
highCVE-2026-74702: In the Linux kernel, the following vulnerability has been resolved: vhost-scsi: reject feature…nvd · 2026-08-22
highCVE-2026-74580: In the Linux kernel, the following vulnerability has been resolved: vhost: reset the vring met…nvd · 2026-08-21
criticalCVE-2026-68004: An issue in OSSRS SRS (Simple Realtime Server) <v5.0.213 allows a remote attacker to execute a…nvd · 2026-08-17
highCVE-2026-74356: In the Linux kernel, the following vulnerability has been resolved: vhost: fix vhost_get_avail…nvd · 2026-08-15