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CVE-2026-45894— iommu/vt-d: Clear Present bit before tearing down PASID 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.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于Intel VT-d驱动在清除PASID表项时未先清除Present位，可能导致硬件读取不一致状态。

CVSS 7.8 · High EPSS 0.15% · P4

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15< a84d30e8d2bacd21782a6481158b7c9c552f4868 affected
0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15< 821807c167b7b48a41b95b6607c6b9f97600f7d9 affected
0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15< 949d71666e9dd19f21e7b4b53a88cd2c5b902858 affected
0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15< 75ed00055c059dedc47b5daaaa2f8a7a019138ff affected
5.0 affected
< 5.0 unaffected
6.12.75≤ 6.12.* unaffected
6.18.14≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-45894

Vulnerability Information
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Vulnerability Title
iommu/vt-d: Clear Present bit before tearing down PASID 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 PASID entry The Intel VT-d Scalable Mode PASID table entry consists of 512 bits (64 bytes). When tearing down an entry, the current implementation zeros the entire 64-byte structure immediately using multiple 64-bit writes. Since the IOMMU hardware may fetch these 64 bytes using multiple internal transactions (e.g., four 128-bit bursts), updating or zeroing the entire entry while it is active (P=1) risks a "torn" read. If a hardware fetch occurs simultaneously with the CPU zeroing the entry, the hardware could observe an inconsistent state, leading to unpredictable behavior or spurious faults. Follow the "Guidance to Software for Invalidations" in the VT-d spec (Section 6.5.3.3) by implementing the recommended ownership handshake: 1. Clear only the 'Present' (P) bit of the PASID entry. 2. Use a dma_wmb() to ensure the cleared bit is visible to hardware before proceeding. 3. Execute the required invalidation sequence (PASID cache, IOTLB, and Device-TLB flush) to ensure the hardware has released all cached references. 4. Only after the flushes are complete, zero out the remaining fields of the PASID entry. Also, add a dma_wmb() in pasid_set_present() to ensure that all other fields of the PASID entry are visible to the hardware before the Present bit is set.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:H/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
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于Intel VT-d驱动在清除PASID表项时未先清除Present位，可能导致硬件读取不一致状态。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 0bbeb01a4fafbf8422e5c8882d461d6ac4f71e15 ~ a84d30e8d2bacd21782a6481158b7c9c552f4868 -
Linux Linux 5.0 -

II. Public POCs for CVE-2026-45894

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III. Intelligence Information for CVE-2026-45894

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Patches & Fixes for CVE-2026-45894 (4)

Same Patch Batch · Linux · 2026-05-27 · 275 CVEs total

CVE-2026-45898 9.8 CRITICAL RDMA/iwcm: Fix workqueue list corruption by removing work_list
CVE-2026-46039 9.8 CRITICAL rxgk: Fix potential integer overflow in length check
CVE-2026-45988 9.8 CRITICAL rxrpc: Fix re-decryption of RESPONSE packets
CVE-2026-45972 9.8 CRITICAL smb: client: fix potential UAF and double free in smb2_open_file()
CVE-2026-46043 9.1 CRITICAL RDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv
CVE-2026-45945 8.8 HIGH iommu/vt-d: Fix race condition during PASID entry replacement
CVE-2026-46056 8.8 HIGH Bluetooth: hci_event: fix potential UAF in SSP passkey handlers
CVE-2026-45843 8.2 HIGH slip: bound decode() reads against the compressed packet length
CVE-2026-46037 8.2 HIGH ipv4: icmp: validate reply type before using icmp_pointers
CVE-2025-71311 8.2 HIGH fs/ntfs3: Initialize new folios before use
CVE-2026-46010 8.1 HIGH rxrpc: Fix error handling in rxgk_extract_token()
CVE-2026-46099 8.1 HIGH net: ipv6: fix NOREF dst use in seg6 and rpl lwtunnels
CVE-2026-46076 7.9 HIGH KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1
CVE-2026-45933 7.8 HIGH bpf: Preserve id of register in sync_linked_regs()
CVE-2026-45951 7.8 HIGH bpf: Fix a potential use-after-free of BTF object
CVE-2026-45935 7.8 HIGH fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot
CVE-2026-46015 7.8 HIGH tcp: call sk_data_ready() after listener migration
CVE-2026-45984 7.8 HIGH gfs2: Fix use-after-free in iomap inline data write path
CVE-2026-45862 7.8 HIGH iommu/vt-d: Flush cache for PASID table before using it
CVE-2026-45861 7.8 HIGH gfs2: Fix slab-use-after-free in qd_put

Showing top 20 of 275 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-45894

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