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VulnerabilityPublished Updated

CVE-2026-74580: Linux kernel · vhost: reset the vring metadata cache on vring reconfiguration

Source GCVE Database

0
Authoritative record:CVE-2026-74580· High 8.8

Not known to be exploited · CVSS 8.8 High · fixed in f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6 : patch Linux kernel soon.

Data as of 28 Oct 2026, 22:12 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6, de845981da67a6b049080c87e605130b0c30adc5, cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 21 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: evidence found.

    CISA SSVC: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by kernel.org

    , 6 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. CISA SSVC assessment

    proof of concept public

    , 68 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ f889491380582b4ba2981cf0b0d7d6a40fb30ab7, < f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6
Fixed in
  • f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6
LinuxLinuxAffected
  • ≥ f889491380582b4ba2981cf0b0d7d6a40fb30ab7, < de845981da67a6b049080c87e605130b0c30adc5
Fixed in
  • de845981da67a6b049080c87e605130b0c30adc5
LinuxLinuxAffected
  • ≥ f889491380582b4ba2981cf0b0d7d6a40fb30ab7, < cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7
Fixed in
  • cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7
LinuxLinuxAffected
  • ≥ f889491380582b4ba2981cf0b0d7d6a40fb30ab7, < b70ebe0bba254e093dd5fd4c0c170941ce83eb85
Fixed in
  • b70ebe0bba254e093dd5fd4c0c170941ce83eb85
LinuxLinuxAffected
  • ≥ f889491380582b4ba2981cf0b0d7d6a40fb30ab7, < 54617e9119be2eb728ecdd8d977b99c99d4c498a
Fixed in
  • 54617e9119be2eb728ecdd8d977b99c99d4c498a
LinuxLinuxAffected
  • ≥ f889491380582b4ba2981cf0b0d7d6a40fb30ab7, < 5224bd37e37d36076a550d99b2aebba33939fd95
Fixed in
  • 5224bd37e37d36076a550d99b2aebba33939fd95

Description

In the Linux kernel, the following vulnerability has been resolved: vhost: reset the vring metadata cache on vring reconfiguration vq->meta_iotlb[] caches the vhost_iotlb_map that backs each vring metadata region, and iotlb_access_ok() returns early on a cache hit, taking the hit as proof that the region has already been validated: if (vhost_vq_meta_fetch(vq, addr, len, type)) return true; The cache is reset on VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE, on device IOTLB (re)initialisation and on vq reset, but not when VHOST_SET_VRING_ADDR replaces vq->desc, vq->avail and vq->used, nor when VHOST_SET_VRING_NUM changes the region sizes. With a device IOTLB attached both ioctls are accepted while the vq is live, and neither validates the addresses at ioctl time: vq_access_ok() and vq_log_used_access_ok() return true early because the addresses are GIOVAs, deferring validation to prefetch time. Once the cache has been populated that deferred validation no longer runs -- vq_meta_prefetch() hits the stale entry and returns true -- and vhost_vq_meta_fetch() keeps translating through the old mapping as map->addr + addr - map->start for an address the mapping no longer covers. vhost_copy_to_user() and vhost_copy_from_user() consume the result with __copy_to_user() and __copy_from_user(), which do not check it either, so a subsequent used ring update or descriptor fetch accesses memory outside the region the IOTLB actually maps. Reset the metadata cache whenever the vring is reconfigured, so the new addresses are pushed back through iotlb_access_ok()'s slow path.

References

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