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Fencer Vulns
high 8.8

CVE-2026-89777 json

vfio/pci: clear vdev->msi_perm after freeing it on init failure

published 2026-09-16 54 d ago modified 2026-10-19 21 d ago also EUVD-2026-80298

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

vfio/pci: clear vdev->msi_perm after freeing it on init failure

vfio_msi_cap_len() lazily allocates the per-device MSI permission table:

vdev->msi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT); if (!vdev->msi_perm) return -ENOMEM;

ret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags); if (ret) { kfree(vdev->msi_perm); return ret; /* vdev->msi_perm left dangling */ }

When init_pci_cap_msi_perm() -> alloc_perm_bits() fails with -ENOMEM, the error path frees vdev->msi_perm but leaves the freed pointer stored in it. vdev->msi_perm is not re-zeroed later because struct vfio_pci_core_device is per-device and persists across open/close cycles, and the vfio_config_init() error path returns without calling vfio_config_free(). So the dangling pointer outlives the failed open.

That leads to two use-after-frees on the same device:

1. Reuse. The next vfio_config_init() sees the stale pointer at "if (vdev->msi_perm) return len;" and reuses the freed object. MSI config accesses in vfio_pci_config_rw_single() then dereference and call the freed perm->readfn / perm->writefn function pointers.

2. Double free. A later vfio_config_free() runs free_perm_bits() and kfree() on the already-freed object.

Fix it by NULLing vdev->msi_perm after the kfree(), matching the NULL-after-free discipline already used in free_perm_bits() and vfio_config_free().

BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961) Read of size 8 at addr ffff88800fcc88d0 by task exploit/143 Call Trace: ... kasan_report (mm/kasan/report.c:595) vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961) vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986) vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599) vfs_read (fs/read_write.c:572) __x64_sys_pread64 (fs/read_write.c:764) do_syscall_64 (arch/x86/entry/syscall_64.c:94) ...

Followed on device close by a double free of the same object:

Oops: general protection fault, probably for non-canonical address 0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI RIP: 0010:kfree (mm/slub.c:6711) Call Trace: vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861) vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685) vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777) vfio_df_close (drivers/vfio/vfio_main.c:602) vfio_device_fops_release (drivers/vfio/vfio_main.c:648) __fput (fs/file_table.c:512) __x64_sys_close (fs/open.c:1496) do_syscall_64 (arch/x86/entry/syscall_64.c:94) ... Kernel panic - not syncing: Fatal exception

Patch / fix

  • Linux Linux 4.5, 4.10, 4.15, 4.20, 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-89777

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-89777

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.2.7-1.1

opensuse advisories openSUSE-SU-2026:11880-1

  • kernel AlmaLinux 10 6.12.0-211.69.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.69.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.69.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.69.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.69.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.69.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.69.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.69.1.el10_2

almalinux advisories ALSA-2026:91565ALSA-2026:90365ALSA-2026:87374ALSA-2026:87375

  • kernel Rocky Linux 9 5.14.0-687.61.1.el9_8.cloud.1.0
  • kernel Rocky Linux 10 6.12.0-211.69.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.61.1.el9_8
  • kernel-rt Rocky Linux 8 4.18.0-553.177.1.rt7.518.el8_10
  • kernel Rocky Linux 8 4.18.0-553.177.1.el8_10

rocky linux advisories RXSA-2026:90365RLSA-2026:91565RLSA-2026:90365RLSA-2026:87374RLSA-2026:87375

  • kernel Azure Linux 3.0 6.6.157.1-1

azure linux advisories AZL-101571

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-89777 updated cvss 7.8

kernel: vfio/pci: clear vdev->msi_perm after freeing it on init failure

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8
    affected: workaround, no fix available
  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.69.1.el10_2
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.61.1.el9_8, perf 5.14.0-687.61.1.el9_8, rtla 5.14.0-687.61.1.el9_8, python3-perf 5.14.0-687.61.1.el9_8, kernel-devel-matched 5.14.0-687.61.1.el9_8, kernel-64k-devel-matched 5.14.0-687.61.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:90365
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.69.1.el10_2, perf 6.12.0-211.69.1.el10_2, rtla 6.12.0-211.69.1.el10_2, python3-perf 6.12.0-211.69.1.el10_2, kernel-devel-matched 6.12.0-211.69.1.el10_2, kernel-64k-devel-matched 6.12.0-211.69.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.177.1.el8_10, kernel 4.18.0-553.177.1.el8_10, bpftool 4.18.0-553.177.1.el8_10, kernel-core 4.18.0-553.177.1.el8_10, kernel-tools 4.18.0-553.177.1.el8_10, python3-perf 4.18.0-553.177.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:87375
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.61.1.el9_8, kernel-64k 5.14.0-687.61.1.el9_8, kernel-core 5.14.0-687.61.1.el9_8, kernel-tools 5.14.0-687.61.1.el9_8, kernel-modules 5.14.0-687.61.1.el9_8, kernel-64k-core 5.14.0-687.61.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:90365
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.69.1.el10_2, kernel-64k 6.12.0-211.69.1.el10_2, kernel-core 6.12.0-211.69.1.el10_2, kernel-tools 6.12.0-211.69.1.el10_2, kernel-modules 6.12.0-211.69.1.el10_2, kernel-64k-core 6.12.0-211.69.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.61.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.61.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.61.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.61.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.61.1.el9_8
    fixed: vendor fix RHSA-2026:90365
show 12 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.69.1.el10_2
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.177.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.177.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.177.1.el8_10
    fixed: vendor fix RHSA-2026:87375
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.69.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.69.1.el10_2
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-kvm 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-core 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-modules 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-debug-kvm 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-debug-core 4.18.0-553.177.1.rt7.518.el8_10, +4 more
    fixed: vendor fix RHSA-2026:87374
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.61.1.el9_8, kernel-rt-64k 5.14.0-687.61.1.el9_8, kernel-rt-core 5.14.0-687.61.1.el9_8, kernel-rt-modules 5.14.0-687.61.1.el9_8, kernel-rt-64k-core 5.14.0-687.61.1.el9_8, kernel-rt-debug-core 5.14.0-687.61.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:90365
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.69.1.el10_2, kernel-rt-64k 6.12.0-211.69.1.el10_2, kernel-rt-core 6.12.0-211.69.1.el10_2, kernel-rt-modules 6.12.0-211.69.1.el10_2, kernel-rt-64k-core 6.12.0-211.69.1.el10_2, kernel-rt-debug-core 6.12.0-211.69.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.61.1.el9_8, kernel-rt-core 5.14.0-687.61.1.el9_8, kernel-rt-modules 5.14.0-687.61.1.el9_8, kernel-rt-debug-core 5.14.0-687.61.1.el9_8, kernel-rt-modules-core 5.14.0-687.61.1.el9_8, kernel-rt-debug-modules 5.14.0-687.61.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:90365
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.69.1.el10_2, kernel-rt-core 6.12.0-211.69.1.el10_2, kernel-rt-modules 6.12.0-211.69.1.el10_2, kernel-rt-debug-core 6.12.0-211.69.1.el10_2, kernel-rt-modules-core 6.12.0-211.69.1.el10_2, kernel-rt-debug-modules 6.12.0-211.69.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:91565
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-core 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-modules 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-debug-core 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-debug-modules 4.18.0-553.177.1.rt7.518.el8_10, kernel-rt-modules-extra 4.18.0-553.177.1.rt7.518.el8_10, +2 more
    fixed: vendor fix RHSA-2026:87374
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202611032353
    fixed: vendor fix RHSA-2026:95346
  • Red Hat OpenShift Container Platform 5.0 rhcos 5.0.9.8.202611022248, rhcos 5.0.10.2.202611022203
    fixed: vendor fix RHSA-2026:94537
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.