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CVE-2026-89777

Vulnérabilité élevée dans Linux (Linux)

CVSS 8.8 · Élevée
EPSS 0.2%
Linux•Linux•Versions : <d665a1688af7f8fefd7c0eb04f2a37122ce007f4, <=6.1.*, <=6.12.*, 4.19.85, 4.14.155, 4.20, 5.15.221, dde3433de9a067a33d67d65b9093cad3e043e49e, 4.4.203, 5.10.270, 0, <4.10, 6.1.188, 6.18.52, <eb84cd81040e58dd05ac190f561f2115e3367249, <dc77acfeb979dded39b247b60fef0399536bfa77, <4.20, <=5.10.*, <f0eea8f9013676b42289ec35941e848b8a543e19, <=6.6.*, 6.6.157, f1b10ba5739440ca51d66f0b2949cead88d2dd02, <4.5, 7.2.6, 30ea32ab1951c80c6113f300fce2c70cd12659e4, <=6.18.*, 6.12.110, <=7.2.*, <812f1db7f0755a19ef16ecdc5cec51bcabc5eda5, <533d0c5feef85ee6404b9f41d5564fac6971a008, 4.9.203, <=*, <=5.15.*, <25cdd2a492d868cff1e519a60fe282909c52d385, ac370e3d1f3b01519d2705cd5815d1c9d0a8812b, be363e27ec3c3a99793da2be6c07eafb95709c6b, <4.15, <fda8fb7e8179561693a786a7af593f6b944a21c1, 7.3

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

Gravité et risque d'exploitation

CVE-2026-89777 obtient un score CVSS de 8.8/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.16 %, ce qui la place devant 5.3 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <d665a1688af7f8fefd7c0eb04f2a37122ce007f4, <=6.1.*, <=6.12.*, 4.19.85, 4.14.155, 4.20, 5.15.221, dde3433de9a067a33d67d65b9093cad3e043e49e, 4.4.203, 5.10.270, 0, <4.10, 6.1.188, 6.18.52, <eb84cd81040e58dd05ac190f561f2115e3367249, <dc77acfeb979dded39b247b60fef0399536bfa77, <4.20, <=5.10.*, <f0eea8f9013676b42289ec35941e848b8a543e19, <=6.6.*, 6.6.157, f1b10ba5739440ca51d66f0b2949cead88d2dd02, <4.5, 7.2.6, 30ea32ab1951c80c6113f300fce2c70cd12659e4, <=6.18.*, 6.12.110, <=7.2.*, <812f1db7f0755a19ef16ecdc5cec51bcabc5eda5, <533d0c5feef85ee6404b9f41d5564fac6971a008, 4.9.203, <=*, <=5.15.*, <25cdd2a492d868cff1e519a60fe282909c52d385, ac370e3d1f3b01519d2705cd5815d1c9d0a8812b, be363e27ec3c3a99793da2be6c07eafb95709c6b, <4.15, <fda8fb7e8179561693a786a7af593f6b944a21c1, 7.3) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

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