Incorrect Check of Function Return Value Affecting kernel-rt-core package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.24% (15th percentile)

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  • Snyk IDSNYK-CENTOS10-KERNELRTCORE-18972819
  • published20 Aug 2026
  • disclosed15 Aug 2026

Introduced: 15 Aug 2026

NewCVE-2026-74356  (opens in a new tab)
CWE-253  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel-rt-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-core package and not the kernel-rt-core package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

vhost: fix vhost_get_avail_idx for a non empty ring

vhost_get_avail_idx is supposed to report whether it has updated vq->avail_idx. Instead, it returns whether all entries have been consumed, which is usually the same. But not always - in drivers/vhost/net.c and when mergeable buffers have been enabled, the driver checks whether the combined entries are big enough to store an incoming packet. If not, the driver re-enables notifications with available entries still in the ring. The incorrect return value from vhost_get_avail_idx propagates through vhost_enable_notify and causes the host to livelock if the guest is not making progress, as vhost will immediately disable notifications and retry using the available entries.

This goes back to commit d3bb267bbdcb ("vhost: cache avail index in vhost_enable_notify()") which changed vhost_enable_notify() to compare the freshly read avail index against vq->last_avail_idx instead of the previously cached vq->avail_idx. Commit 7ad472397667 ("vhost: move smp_rmb() into vhost_get_avail_idx()") then carried over the same comparison when refactoring vhost_enable_notify() to call the unified vhost_get_avail_idx().

The obvious fix is to make vhost_get_avail_idx do what the comment says it does and report whether new entries have been added.

CVSS Base Scores

version 3.1