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CVE-2026-89957— s390/vfio-ap: Fix hot-unplug skipped when last AP adapter or domain removed

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： s390/vfio-ap：修复当移除最后一个 AP 适配器或域时，热拔出操作被跳过的缺陷 函数通过 的返回值来判断是否需要更新来宾（guest）的 APCB（AP Configuration Block）。然而， 在结果位图（bitmap）为空时会返回 。这意味着，如果分配给某个 mdev 的最后一个适配器、域或控制域从宿主机的 AP 配置中被移除时，相应的位虽然会从影子 APCB（shadow APCB）中正确清除，但 会因结果为空位图而返回 。结果导致 保持为 0， 从

CVSS 8.8 · High EPSS 0.18% · P7

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux eeb386aeb5b7c8d2dae6a3ba49255d8a97803182< f58e824de8577fe411f6199d659731a0f86a7275 affected
eeb386aeb5b7c8d2dae6a3ba49255d8a97803182< 3a9b049bbdc40165d7f3e20b818eec95e5694d96 affected
eeb386aeb5b7c8d2dae6a3ba49255d8a97803182< 753aa3bb1273bc0d36adb013d5915cc8ff6b72a9 affected
eeb386aeb5b7c8d2dae6a3ba49255d8a97803182< c45753c32d452d10d8efaeb52587e9e6e8126e33 affected
eeb386aeb5b7c8d2dae6a3ba49255d8a97803182< 04b35dd88c108b2d2ceaaa396aba1cb4049d5831 affected
eeb386aeb5b7c8d2dae6a3ba49255d8a97803182< 917f509bfb88048094dbb85c4e9dbc4d6fe4a886 affected
6.0 affected
< 6.0 unaffected
… +6 more rows
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I. Basic Information for CVE-2026-89957

Vulnerability Information
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Vulnerability Title
s390/vfio-ap: Fix hot-unplug skipped when last AP adapter or domain removed
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: s390/vfio-ap: Fix hot-unplug skipped when last AP adapter or domain removed The vfio_ap_mdev_hot_unplug_cfg() function uses the return value of bitmap_andnot() to determine whether the guest APCB needs to be updated. However, bitmap_andnot() returns false when the resulting destination bitmap is empty. This means that if the only adapter, domain or control domain assigned to an mdev is removed from the host's AP configuration, the bit is correctly cleared from the shadow APCB, but bitmap_andnot() returns false because the result is an empty bitmap. Consequently, do_hotplug remains 0 and vfio_ap_mdev_update_guest_apcb() is never called, leaving the KVM guest with stale hardware access to the unplugged AP devices. Fix this by replacing the bitmap_andnot() return value check with bitmap_intersects() to determine whether the shadow APCB actually overlaps with the removal mask. If there is an intersection, call bitmap_andnot() solely for its side effect of clearing the bits, then unconditionally set do_hotplug to trigger the guest APCB update.
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 eeb386aeb5b7c8d2dae6a3ba49255d8a97803182 ~ f58e824de8577fe411f6199d659731a0f86a7275 -
Linux Linux 6.0 -

II. Public POCs for CVE-2026-89957

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III. Intelligence Information for CVE-2026-89957

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Other References for CVE-2026-89957 (6)

Same Patch Batch · Linux · 2026-09-16 · 276 CVEs total

CVE-2026-90048 9.8 CRITICAL fs/ntfs3: fix slab-out-of-bounds write in ni_create_attr_list()
CVE-2026-90012 9.8 CRITICAL spi: Fix DMA mapping ownership on partial map failure
CVE-2026-89970 9.8 CRITICAL nvmet-auth: Synchronize timeout work during SQ teardown
CVE-2026-89857 9.8 CRITICAL scsi: qla2xxx: Hold qpair lock when sending NVMe LS reject
CVE-2026-89969 9.8 CRITICAL nvmet-tcp: fix out-of-bounds write when receiving an over-long PDU
CVE-2026-89847 9.8 CRITICAL scsi: qla2xxx: Avoid double completion in async IOCB timeout
CVE-2026-89972 9.8 CRITICAL nvme: add missing SRCU grace period in error path
CVE-2026-89990 9.8 CRITICAL ceph: lock mutex in ceph_mds_check_access()
CVE-2026-90036 9.8 CRITICAL NFSD: Prevent client use-after-free during blocked-lock reaping
CVE-2026-90038 9.8 CRITICAL NFSD: Prevent client use-after-free during export state revocation
CVE-2026-90037 9.8 CRITICAL NFSD: Prevent client use-after-free during close_lru reaping
CVE-2026-89788 9.8 CRITICAL ksmbd: fix tree connection use-after-free in smb2_tree_connect()
CVE-2026-89783 9.8 CRITICAL xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full
CVE-2026-90042 9.8 CRITICAL ceph: properly decrypt filenames in vmalloc() buffers
CVE-2026-89778 9.8 CRITICAL isofs: fix out-of-bounds page array access on empty zisofs block
CVE-2026-89914 9.3 CRITICAL KVM: arm64: Sign-extend VA for range-based TLBI invalidation
CVE-2026-90049 9.3 CRITICAL net: skbuff: don't skb_tx_error() the source skb in skb_zerocopy()
CVE-2026-89775 9.3 CRITICAL KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation
CVE-2026-89916 9.3 CRITICAL KVM: arm64: Make VNCR invalidation participate in MMU invalidation retry
CVE-2026-89930 9.3 CRITICAL KVM: nVMX: Service local TLB flushes on failed nested VM-Enter

Showing top 20 of 276 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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