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CVE-2026-90243— iommu/vt-d: Clear Present bit before tearing down copied context entry

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，已修复如下漏洞： iommu/vt-d: 在拆除复制上下文条目前先清除“Present”位 函数在“Present”位仍然置位的情况下，调用 将 128 位上下文条目清零，之后才发起上下文缓存和 IOTLB 失效操作。这会导致一个时间窗口：硬件可能获取到一个“撕裂”的条目——部分字段已被清零，而 Present 位仍为置位状态，从而导致不可预测的行为或虚假故障。虽然 x86 架构提供了较强的写顺序保证，但编译器可能会对条目的两个 64 位半字进行写操作的重排序；此外，硬件对该条目的读取并不保

AI Predicted 4.6 Difficulty: Hard

Possible ATT&CK Techniques 1 AI

T1610 · Deploy Container

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux c7191984e5aade540f1a3845a116537c89572655< 97750a8dce79c1a9b2b2d2a020b61b800141996c affected
c7191984e5aade540f1a3845a116537c89572655< 3c88cfedc7768b1ae2dc7ddc71547ae9a1aaff7d affected
c7191984e5aade540f1a3845a116537c89572655< 6b822d18c33af9d1e16a8e5e6aa6e656987b09de affected
c7191984e5aade540f1a3845a116537c89572655< f532c57985b1a7d6b7e37e05506b46d413e5cca4 affected
6.12 affected
< 6.12 unaffected
6.12.110≤ 6.12.* unaffected
6.18.52≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-90243

Vulnerability Information
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Vulnerability Title
iommu/vt-d: Clear Present bit before tearing down copied context entry
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Clear Present bit before tearing down copied context entry copied_context_tear_down() zeroes the 128-bit context entry with context_clear_entry() while the Present bit is still set, and only then issues the context-cache and IOTLB invalidations. This leaves a window in which hardware can fetch a torn entry, with some fields already zeroed while Present is still set, leading to unpredictable behaviour or spurious faults. While x86 provides strong write ordering, the compiler may reorder the writes to the two 64-bit halves of the entry, and the hardware fetch is not guaranteed to be atomic with respect to multiple CPU writes. There is no cacheline flush before the invalidation either, so on an IOMMU without coherent access to the context table the zeroed entry may not be visible to hardware at the point the invalidation is submitted. Apply the same ownership handshake described in the VT-d spec, Section 6.5.3.3 ("Guidance to Software for Invalidations"): clear only the Present bit, flush it out to the IOMMU, perform the invalidations, and only then zero the remainder of the entry.
Source: CVE Program / CVE List V5
CVSS Information
N/A
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 c7191984e5aade540f1a3845a116537c89572655 ~ 97750a8dce79c1a9b2b2d2a020b61b800141996c -
Linux Linux 6.12 -

II. Public POCs for CVE-2026-90243

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III. Intelligence Information for CVE-2026-90243

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Patches & Fixes for CVE-2026-90243 (2)

Other References for CVE-2026-90243 (2)

Same Patch Batch · Linux · 2026-09-17 · 602 CVEs total

CVE-2026-90257 Bluetooth: virtio_bt: avoid OOB read of build info string
CVE-2026-90238 media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
CVE-2026-90240 iommu/vt-d: Flush context cache with correct SID when tearing down aliases
CVE-2026-90239 media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
CVE-2026-90241 iommu/vt-d: Tear down scalable-mode context on probe failure
CVE-2026-90242 iommu/vt-d: Fix iopf_refcount leak on RID domain replacement
CVE-2026-90244 iommu/dma: Restore locking around msi_page_list
CVE-2026-90245 fbdev: kyro: Validate overlay viewport coordinates
CVE-2026-90246 apparmor: fix integer overflow in verify_tags() bounds check
CVE-2026-90247 bpf: Fix mmap_lock leak in irq_work path
CVE-2026-90248 net/sched: cls_api: fix teardown of an adopted proto on insert-race loss
CVE-2026-90249 iio: light: gp2ap002: Fix unbalanced runtime PM on repeated event writes
CVE-2026-90250 bpf, cgroup: Fix storage null-ptr-deref after replacing prog
CVE-2026-90251 Bluetooth: MSFT: validate evt_prefix_len against the response length
CVE-2026-90253 Bluetooth: MGMT: free the mesh send cancel command when it is cancelled
CVE-2026-90252 Bluetooth: MGMT: free the HCI command when it is cancelled
CVE-2026-90254 Bluetooth: hci_sync: free the advertising instance on the failure and cancel paths
CVE-2026-90256 Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind
CVE-2026-90255 Bluetooth: hci_conn: fix the SCO setup context lifetime
CVE-2026-90267 scsi: sd: Fix special_vec mempool leak when scsi_alloc_sgtables() fails

Showing top 20 of 602 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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