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CVE-2026-74580— vhost: reset the vring metadata cache on vring reconfiguration

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，已修复以下漏洞： vhost：在 vring 重新配置时重置 vring 元数据缓存 缓存用于支持每个 vring 元数据区域的 。 在缓存命中时提前返回，并将此命中视为该区域已通过验证的证明： 该缓存在以下情况下会被重置： 和 发生时、设备 IOTLB（重新）初始化时、以及 vq 重置时。但在以下情况下不会重置： 替换 、 和 时，或 更改区域大小时。 当附加了设备 IOTLB 时，这两个 ioctl 调用在 vq 处于活跃状态时均可被接受，且在 ioctl 调用时不会验证地址： 和 由于

CVSS 8.8 · High EPSS 0.17% · P6

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux f889491380582b4ba2981cf0b0d7d6a40fb30ab7< 5224bd37e37d36076a550d99b2aebba33939fd95 affected
f889491380582b4ba2981cf0b0d7d6a40fb30ab7< 54617e9119be2eb728ecdd8d977b99c99d4c498a affected
f889491380582b4ba2981cf0b0d7d6a40fb30ab7< 13fa6f32a56a386a82bd7451644c494beed034af affected
f889491380582b4ba2981cf0b0d7d6a40fb30ab7< cf363a7a02ce132ef1f58084fdb13e1a3b7da7e7 affected
f889491380582b4ba2981cf0b0d7d6a40fb30ab7< 6fa3e9b1fe856259555a7e22f3f3082e7827fd9b affected
f889491380582b4ba2981cf0b0d7d6a40fb30ab7< f1e21108e3ddfcce62f6cad4ebd7b5674543c9e6 affected
f889491380582b4ba2981cf0b0d7d6a40fb30ab7< b70ebe0bba254e093dd5fd4c0c170941ce83eb85 affected
f889491380582b4ba2981cf0b0d7d6a40fb30ab7< de845981da67a6b049080c87e605130b0c30adc5 affected
… +10 more rows
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I. Basic Information for CVE-2026-74580

Vulnerability Information
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Vulnerability Title
vhost: reset the vring metadata cache on vring reconfiguration
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux f889491380582b4ba2981cf0b0d7d6a40fb30ab7 ~ 5224bd37e37d36076a550d99b2aebba33939fd95 -
Linux Linux 4.11 -

II. Public POCs for CVE-2026-74580

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III. Intelligence Information for CVE-2026-74580

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Patches & Fixes for CVE-2026-74580 (8)

Same Patch Batch · Linux · 2026-08-21 · 4 CVEs total

CVE-2026-74581 9.8 CRITICAL net: ipv6: clear suppressed fib6 rule result
CVE-2026-74583 7.8 HIGH net/sched: cls_route: fix fastmap use-after-free on filter
CVE-2026-74582 7.8 HIGH packet: use consistent hard_header_len in non-ring send paths

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-74580

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