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CVE-2024-26786 (GCVE-0-2024-26786)

Vulnerability from cvelistv5 – Published: 2024-04-04 08:20 – Updated: 2026-08-05 11:27
VLAI
Title
iommufd: Fix iopt_access_list_id overwrite bug
Summary
In the Linux kernel, the following vulnerability has been resolved: iommufd: Fix iopt_access_list_id overwrite bug Syzkaller reported the following WARN_ON: WARNING: CPU: 1 PID: 4738 at drivers/iommu/iommufd/io_pagetable.c:1360 Call Trace: iommufd_access_change_ioas+0x2fe/0x4e0 iommufd_access_destroy_object+0x50/0xb0 iommufd_object_remove+0x2a3/0x490 iommufd_object_destroy_user iommufd_access_destroy+0x71/0xb0 iommufd_test_staccess_release+0x89/0xd0 __fput+0x272/0xb50 __fput_sync+0x4b/0x60 __do_sys_close __se_sys_close __x64_sys_close+0x8b/0x110 do_syscall_x64 The mismatch between the access pointer in the list and the passed-in pointer is resulting from an overwrite of access->iopt_access_list_id, in iopt_add_access(). Called from iommufd_access_change_ioas() when xa_alloc() succeeds but iopt_calculate_iova_alignment() fails. Add a new_id in iopt_add_access() and only update iopt_access_list_id when returning successfully.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-07-15 16:04 UTC
CWE
  • CWE-476 - NULL Pointer Dereference
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 9227da7816dd1a42e20d41e2244cb63c205477ca , < f1fb745ee0a6fe43f1d84ec369c7e6af2310fda9 (git)
Affected: 9227da7816dd1a42e20d41e2244cb63c205477ca , < 9526a46cc0c378d381560279bea9aa34c84298a0 (git)
Affected: 9227da7816dd1a42e20d41e2244cb63c205477ca , < aeb004c0cd6958e910123a1607634401009c9539 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.6
Unaffected: 0 , < 6.6 (semver)
Unaffected: 6.6.21 , ≤ 6.6.* (semver)
Unaffected: 6.7.9 , ≤ 6.7.* (semver)
Unaffected: 6.8 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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      "initial_release_date": "2024-04-04T00:00:00+00:00",
      "product_status:fixed": "280",
      "product_status:known_affected": "22",
      "product_status:known_not_affected": "98",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: iommufd: Fix iopt_access_list_id overwrite bug",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-26786.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://git.kernel.org/stable/c/f1fb745ee0a6fe43f1d84ec369c7e6af2310fda9\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/9526a46cc0c378d381560279bea9aa34c84298a0\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/aeb004c0cd6958e910123a1607634401009c9539\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-02T00:14:13.526Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.5, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2024-26786\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-07-15T16:04:45.617050Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-476\", \"description\": \"CWE-476 NULL Pointer Dereference\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-07-15T16:05:06.270Z\"}}], \"cna\": {\"title\": \"iommufd: Fix iopt_access_list_id overwrite bug\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.8, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:L - The bug is reached only through ioctls on local character devices \\u2014 `/dev/iommu` or `/dev/vfio/vfio` (`IOMMU_IOAS_MAP`/`IOMMU_IOAS_UNMAP`) plus `VFIO_DEVICE_ATTACH_IOMMUFD_PT` on an emulated VFIO device fd. No network or adjacent-network path exists.\\nAC:L - The failure is fully deterministic and attacker-scripted: a fresh IOAS has `iova_alignment = 1`, so mapping at an unaligned IOVA guarantees `iopt_calculate_iova_alignment()` returns `-EADDRINUSE` when an access with `needs_pin_pages` is attached, and `xa_alloc()` hands out the lowest free index so the id collision is predictable. No race and no uncontrolled memory layout are involved.\\nPR:L - iommufd performs no capability check on open or on any ioctl; access is gated only by device-node permissions, and `/dev/vfio/vfio` is registered with `.mode = 0666` while `/dev/iommu` is routinely granted to the unprivileged VMM/qemu user that owns mdev devices. An ordinary local user in a virtualization deployment can drive the entire sequence without root.\\nUI:N - The attacker performs every step \\u2014 IOAS allocation, the unaligned map, the failing attach/replace, and the destroy that leaves the dangling entry \\u2014 entirely within its own process. No victim action is required.\\nS:U - The corrupted state and the resulting memory corruption both live in kernel memory under the same security authority as the attacking local process. The page pins held by the stale access prevent an actual DMA/IOMMU isolation escape, so no security boundary is crossed.\\nC:H - The freed `struct iommufd_access` remains linked in `iopt-\u003eaccess_list` and is dereferenced by `iopt_calculate_iova_alignment()` and `iommufd_access_notify_unmap()`; controlling the reclaimed slab object turns this use-after-free into an arbitrary kernel-memory read primitive.\\nI:H - `iommufd_access_notify_unmap()` performs `access-\u003eops-\u003eunmap(access-\u003edata, ...)` \\u2014 an indirect call through a function-pointer table read from freed, sprayable `GFP_KERNEL_ACCOUNT` memory with an attacker-chosen first argument \\u2014 plus a refcount increment into the freed object, yielding control-flow hijack and arbitrary write.\\nA:H - The mismatch trips `WARN_ON()` in `iopt_remove_access()` (fatal under `panic_on_warn`), the use-after-free readily oopses, and a silently unlinked access drives `iopt_unmap_iova_range()` through its 100-retry loop to `WARN_ON` + `-EDEADLOCK`, permanently wedging unmap on that IOAS.\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"9227da7816dd1a42e20d41e2244cb63c205477ca\", \"lessThan\": \"f1fb745ee0a6fe43f1d84ec369c7e6af2310fda9\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"9227da7816dd1a42e20d41e2244cb63c205477ca\", \"lessThan\": \"9526a46cc0c378d381560279bea9aa34c84298a0\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"9227da7816dd1a42e20d41e2244cb63c205477ca\", \"lessThan\": \"aeb004c0cd6958e910123a1607634401009c9539\", \"versionType\": \"git\"}], \"programFiles\": [\"drivers/iommu/iommufd/io_pagetable.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"6.6\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"6.6\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"6.6.21\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.7.9\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.7.*\"}, {\"status\": \"unaffected\", \"version\": \"6.8\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"drivers/iommu/iommufd/io_pagetable.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/f1fb745ee0a6fe43f1d84ec369c7e6af2310fda9\"}, {\"url\": \"https://git.kernel.org/stable/c/9526a46cc0c378d381560279bea9aa34c84298a0\"}, {\"url\": \"https://git.kernel.org/stable/c/aeb004c0cd6958e910123a1607634401009c9539\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\niommufd: Fix iopt_access_list_id overwrite bug\\n\\nSyzkaller reported the following WARN_ON:\\n  WARNING: CPU: 1 PID: 4738 at drivers/iommu/iommufd/io_pagetable.c:1360\\n\\n  Call Trace:\\n   iommufd_access_change_ioas+0x2fe/0x4e0\\n   iommufd_access_destroy_object+0x50/0xb0\\n   iommufd_object_remove+0x2a3/0x490\\n   iommufd_object_destroy_user\\n   iommufd_access_destroy+0x71/0xb0\\n   iommufd_test_staccess_release+0x89/0xd0\\n   __fput+0x272/0xb50\\n   __fput_sync+0x4b/0x60\\n   __do_sys_close\\n   __se_sys_close\\n   __x64_sys_close+0x8b/0x110\\n   do_syscall_x64\\n\\nThe mismatch between the access pointer in the list and the passed-in\\npointer is resulting from an overwrite of access-\u003eiopt_access_list_id, in\\niopt_add_access(). Called from iommufd_access_change_ioas() when\\nxa_alloc() succeeds but iopt_calculate_iova_alignment() fails.\\n\\nAdd a new_id in iopt_add_access() and only update iopt_access_list_id when\\nreturning successfully.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.21\", \"versionStartIncluding\": \"6.6\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.7.9\", \"versionStartIncluding\": \"6.6\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.8\", \"versionStartIncluding\": \"6.6\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T11:27:14.106Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2024-26786\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T11:27:14.106Z\", \"dateReserved\": \"2024-02-19T14:20:24.178Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-04-04T08:20:19.109Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.