CVE-2026-74356vhost: fix vhost_get_avail_idx for a non empty ring
- 7.4HighCVSS base score
- 0.25%Exploitation in 30 daysEPSS · top 84% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Linux
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.4 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVDNVD · Received | 3.1 | High7.4 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.25% · top 84% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.4.
Affected products
- affected d3bb267bbdcba199568f1325743d9d501dea0560 – < 7536f8f72bd24f1ae316c24231faaa3667eba837
- affected d3bb267bbdcba199568f1325743d9d501dea0560 – < 0fe5ca2d56f0122988016e415a074c95925504b7
- affected d3bb267bbdcba199568f1325743d9d501dea0560 – < e115471008111f894c6528d9ab2ce7d0ce306f35
- affected d3bb267bbdcba199568f1325743d9d501dea0560 – < 7f229d27bf27c7e589eca690d8612763a7a4801f
- affected d3bb267bbdcba199568f1325743d9d501dea0560 – < a9326b652bc7acd748d7a1143573845c7924d847
- affected d3bb267bbdcba199568f1325743d9d501dea0560 – < 09861858a68342f851f71c669ac0f69865c32151
- affected 5.18
- unaffected < 5.18
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.97 – ≤ 6.12.*
- unaffected 6.18.40 – ≤ 6.18.*
- unaffected 7.1.5 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References6
- https://git.kernel.org/stable/c/7536f8f72bd24f1ae316c24231faaa3667eba837 (opens in a new tab)
- https://git.kernel.org/stable/c/0fe5ca2d56f0122988016e415a074c95925504b7 (opens in a new tab)
- https://git.kernel.org/stable/c/e115471008111f894c6528d9ab2ce7d0ce306f35 (opens in a new tab)
- https://git.kernel.org/stable/c/7f229d27bf27c7e589eca690d8612763a7a4801f (opens in a new tab)
- https://git.kernel.org/stable/c/a9326b652bc7acd748d7a1143573845c7924d847 (opens in a new tab)
- https://git.kernel.org/stable/c/09861858a68342f851f71c669ac0f69865c32151 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-59503 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-74356)Record last updated .