vhost: reset the vring metadata cache on vring reconfiguration

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74580
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-21 17:16:44 UTC
Updated2026-08-21 17:16:44 UTC
DescriptionIn 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.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected f889491380582b4ba2981cf0b0d7d6a40fb30ab7 5224bd37e37d36076a550d99b2aebba33939fd95 git Not specified
CNA Linux Linux affected f889491380582b4ba2981cf0b0d7d6a40fb30ab7 54617e9119be2eb728ecdd8d977b99c99d4c498a git Not specified
CNA Linux Linux affected f889491380582b4ba2981cf0b0d7d6a40fb30ab7 13fa6f32a56a386a82bd7451644c494beed034af git Not specified
CNA Linux Linux affected f889491380582b4ba2981cf0b0d7d6a40fb30ab7 cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7 git Not specified
CNA Linux Linux affected f889491380582b4ba2981cf0b0d7d6a40fb30ab7 6fa3e9b1fe856259555a7e22f3f3082e7827fd9b git Not specified
CNA Linux Linux affected f889491380582b4ba2981cf0b0d7d6a40fb30ab7 f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6 git Not specified
CNA Linux Linux affected f889491380582b4ba2981cf0b0d7d6a40fb30ab7 b70ebe0bba254e093dd5fd4c0c170941ce83eb85 git Not specified
CNA Linux Linux affected f889491380582b4ba2981cf0b0d7d6a40fb30ab7 de845981da67a6b049080c87e605130b0c30adc5 git Not specified
CNA Linux Linux affected 4.11 Not specified
CNA Linux Linux unaffected 4.11 semver Not specified
CNA Linux Linux unaffected 5.10.265 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.216 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.152 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.104 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.45 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.9 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/5224bd37e37d36076a550d99b2aebba33939fd95 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/13fa6f32a56a386a82bd7451644c494beed034af 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6fa3e9b1fe856259555a7e22f3f3082e7827fd9b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/de845981da67a6b049080c87e605130b0c30adc5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b70ebe0bba254e093dd5fd4c0c170941ce83eb85 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/54617e9119be2eb728ecdd8d977b99c99d4c498a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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