CVE-2026-89777— vfio/pci: clear vdev->msi_perm after freeing it on init failure
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.
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_KERN
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I. Basic Information for CVE-2026-89777
Vulnerability Information
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Vulnerability Title
vfio/pci: clear vdev->msi_perm after freeing it on init failure
Source: CVE Program / CVE List V5
Vulnerability Description
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
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
II. Public POCs for CVE-2026-89777
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Other References for CVE-2026-89777 (8)
Same Patch Batch · Linux · 2026-09-16 · 276 CVEs total
| CVE-2026-89860 | scsi: qla2xxx: Initialize NVMe abort_work once at submission | |
| CVE-2026-89877 | media: saa7164: fix cleanup on resource allocation failure | |
| CVE-2026-89875 | media: ti: vpe: quiesce overflow recovery before freeing streams | |
| CVE-2026-89876 | media: tda18250: fix possible integer overflow | |
| CVE-2026-89874 | media: v4l2-async: avoid deleting unlinked ASC entry on link error | |
| CVE-2026-89872 | media: v4l2-fwnode: Fix fwnode leak in v4l2_fwnode_parse_link | |
| CVE-2026-89873 | media: v4l2-ctrls: validate HEVC EXT SPS RPS counts | |
| CVE-2026-89871 | media: video-i2c: fix kthread error pointer left in kthread_vid_cap on failure | |
| CVE-2026-89870 | media: zoran: Avoid freeing a registered video_device twice | |
| CVE-2026-89869 | media: qcom: iris: use disable_irq() during power-off | |
| CVE-2026-89868 | media: chips-media: wave5: Add timeout while stop_streaming | |
| CVE-2026-89867 | media: chips-media: wave5: Defer job_finish() only when a DEC_PIC was queued | |
| CVE-2026-89866 | media: chips-media: wave5: Resume device before setting EOS flag | |
| CVE-2026-89865 | scsi: qla2xxx: Zero SFP DMA buffer in FRU/I2C bsg handlers | |
| CVE-2026-89864 | scsi: qla2xxx: Bound i2c->length in I2C bsg handlers | |
| CVE-2026-89863 | scsi: qla2xxx: edif: Fix NULL pointer deref in RX SA delete check | |
| CVE-2026-89862 | scsi: qla2xxx: Fix BSG job leak on validate flash image error path | |
| CVE-2026-89861 | scsi: qla2xxx: Hold vport reference in qla24xx_report_id_acquisition() | |
| CVE-2026-89850 | scsi: qla2xxx: Don't query firmware state while chip is down | |
| CVE-2026-89848 | scsi: qla2xxx: Quiesce response IRQ before freeing request queue |
Showing top 20 of 276 CVEs. View all on vendor page → →
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