FKIE_CVE-2026-89777
Vulnerability from fkie_nvd - Published: 2026-09-16 09:17 - Updated: 2026-09-16 15:18
Severity
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
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/vfio/pci/vfio_pci_config.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "eb84cd81040e58dd05ac190f561f2115e3367249",
"status": "affected",
"version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
"versionType": "git"
},
{
"lessThan": "f0eea8f9013676b42289ec35941e848b8a543e19",
"status": "affected",
"version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
"versionType": "git"
},
{
"lessThan": "d665a1688af7f8fefd7c0eb04f2a37122ce007f4",
"status": "affected",
"version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
"versionType": "git"
},
{
"lessThan": "25cdd2a492d868cff1e519a60fe282909c52d385",
"status": "affected",
"version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
"versionType": "git"
},
{
"lessThan": "812f1db7f0755a19ef16ecdc5cec51bcabc5eda5",
"status": "affected",
"version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
"versionType": "git"
},
{
"lessThan": "533d0c5feef85ee6404b9f41d5564fac6971a008",
"status": "affected",
"version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
"versionType": "git"
},
{
"lessThan": "fda8fb7e8179561693a786a7af593f6b944a21c1",
"status": "affected",
"version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
"versionType": "git"
},
{
"lessThan": "dc77acfeb979dded39b247b60fef0399536bfa77",
"status": "affected",
"version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
"versionType": "git"
},
{
"status": "affected",
"version": "ac370e3d1f3b01519d2705cd5815d1c9d0a8812b",
"versionType": "git"
},
{
"status": "affected",
"version": "be363e27ec3c3a99793da2be6c07eafb95709c6b",
"versionType": "git"
},
{
"status": "affected",
"version": "f1b10ba5739440ca51d66f0b2949cead88d2dd02",
"versionType": "git"
},
{
"status": "affected",
"version": "dde3433de9a067a33d67d65b9093cad3e043e49e",
"versionType": "git"
},
{
"lessThan": "4.5",
"status": "affected",
"version": "4.4.203",
"versionType": "semver"
},
{
"lessThan": "4.10",
"status": "affected",
"version": "4.9.203",
"versionType": "semver"
},
{
"lessThan": "4.15",
"status": "affected",
"version": "4.14.155",
"versionType": "semver"
},
{
"lessThan": "4.20",
"status": "affected",
"version": "4.19.85",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/vfio/pci/vfio_pci_config.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.20"
},
{
"lessThan": "4.20",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.52",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/pci: clear vdev-\u003emsi_perm after freeing it on init failure\n\nvfio_msi_cap_len() lazily allocates the per-device MSI permission table:\n\n\tvdev-\u003emsi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT);\n\tif (!vdev-\u003emsi_perm)\n\t\treturn -ENOMEM;\n\n\tret = init_pci_cap_msi_perm(vdev-\u003emsi_perm, len, flags);\n\tif (ret) {\n\t\tkfree(vdev-\u003emsi_perm);\n\t\treturn ret;\t\t/* vdev-\u003emsi_perm left dangling */\n\t}\n\nWhen init_pci_cap_msi_perm() -\u003e alloc_perm_bits() fails with -ENOMEM, the\nerror path frees vdev-\u003emsi_perm but leaves the freed pointer stored in\nit. vdev-\u003emsi_perm is not re-zeroed later because struct\nvfio_pci_core_device is per-device and persists across open/close cycles,\nand the vfio_config_init() error path returns without calling\nvfio_config_free(). So the dangling pointer outlives the failed open.\n\nThat leads to two use-after-frees on the same device:\n\n1. Reuse. The next vfio_config_init() sees the stale pointer at\n \"if (vdev-\u003emsi_perm) return len;\" and reuses the freed object. MSI\n config accesses in vfio_pci_config_rw_single() then dereference and\n call the freed perm-\u003ereadfn / perm-\u003ewritefn function pointers.\n\n2. Double free. A later vfio_config_free() runs free_perm_bits() and\n kfree() on the already-freed object.\n\nFix it by NULLing vdev-\u003emsi_perm after the kfree(), matching the\nNULL-after-free discipline already used in free_perm_bits() and\nvfio_config_free().\n\n BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)\n Read of size 8 at addr ffff88800fcc88d0 by task exploit/143\n Call Trace:\n ...\n kasan_report (mm/kasan/report.c:595)\n vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)\n vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986)\n vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599)\n vfs_read (fs/read_write.c:572)\n __x64_sys_pread64 (fs/read_write.c:764)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n ...\n\nFollowed on device close by a double free of the same object:\n\n Oops: general protection fault, probably for non-canonical address\n 0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI\n RIP: 0010:kfree (mm/slub.c:6711)\n Call Trace:\n vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861)\n vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685)\n vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777)\n vfio_df_close (drivers/vfio/vfio_main.c:602)\n vfio_device_fops_release (drivers/vfio/vfio_main.c:648)\n __fput (fs/file_table.c:512)\n __x64_sys_close (fs/open.c:1496)\n do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n ...\n Kernel panic - not syncing: Fatal exception"
}
],
"id": "CVE-2026-89777",
"lastModified": "2026-09-16T15:18:06.997",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.0,
"impactScore": 6.0,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-09-16T09:17:08.073",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/25cdd2a492d868cff1e519a60fe282909c52d385"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/533d0c5feef85ee6404b9f41d5564fac6971a008"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/812f1db7f0755a19ef16ecdc5cec51bcabc5eda5"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d665a1688af7f8fefd7c0eb04f2a37122ce007f4"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/dc77acfeb979dded39b247b60fef0399536bfa77"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/eb84cd81040e58dd05ac190f561f2115e3367249"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f0eea8f9013676b42289ec35941e848b8a543e19"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/fda8fb7e8179561693a786a7af593f6b944a21c1"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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