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drm/cirrus-qemu: Validate BAR0 size during probe

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: drm/cirrus-qemu: Validate BAR0 size during probe The `cirrus-qemu` driver relies on `CIRRUS_VRAM_SIZE` (4 MB) to validate framebuffer sizes. However, during PCI probe, the driver mapped BAR0 without verifying that its size matches `CIRRUS_VRAM_SIZE`. If a PCI device with a BAR0 smaller than 4 MB is bound to the driver, the mapped VRAM will be smaller than expected. Because validation checks assume 4 MB VRAM, framebuffers larger than the mapped memory can be created. When the display plane is updated (e.g. during release), `cirrus_primary_plane_helper_atomic_update()` copies the framebuffer to VRAM using `drm_fb_memcpy()`. Writing past the end of the mapped I/O memory causes a supervisor write page fault: BUG: unable to handle page fault for address: ffffc9000389c000 ... RIP: 0010:memcpy_toio+0x7c/0xe0 arch/x86/lib/iomem.c:110 ... Call Trace: iosys_map_memcpy_to include/linux/iosys-map.h:285 [inline] drm_fb_memcpy+0x325/0x5d0 drivers/gpu/drm/drm_format_helper.c:442 cirrus_primary_plane_helper_atomic_update+0x98a/0xb00 drivers/gpu/drm/tiny/cirrus-qemu.c:358 drm_atomic_helper_commit_planes+0x626/0xea0 drivers/gpu/drm/drm_atomic_helper.c:3038 drm_atomic_helper_commit_tail+0x60/0x510 drivers/gpu/drm/drm_atomic_helper.c:1989 commit_tail+0x2b1/0x3c0 drivers/gpu/drm/drm_atomic_helper.c:2074 drm_atomic_helper_commit+0xa77/0xb10 drivers/gpu/drm/drm_atomic_helper.c:2312 Fix this by validating in `cirrus_pci_probe()` tha

Announced Source revision 1
Original source ↗

CVE-2026-98142

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98142

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "ab3e023b1b4c9887c9f0f761b47f3f0516bd3434",
        "lessThan": "2a0e7bcff3fa63e7309d2b39e18af59eb8ef2b6e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ab3e023b1b4c9887c9f0f761b47f3f0516bd3434",
        "lessThan": "0b5084a1f070ad1fc34e11945644ae034bbc774c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ab3e023b1b4c9887c9f0f761b47f3f0516bd3434",
        "lessThan": "26bd90c886218f36c9adeab206b0e27b4384e2f6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ab3e023b1b4c9887c9f0f761b47f3f0516bd3434",
        "lessThan": "144f51cd0ccc3ad47a6099917b7bb535611fb18f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ab3e023b1b4c9887c9f0f761b47f3f0516bd3434",
        "lessThan": "92312d333bf700798f92f30406c721bce87506f3",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/gpu/drm/tiny/cirrus-qemu.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.2"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.2",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.111",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.53",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.7",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/gpu/drm/tiny/cirrus-qemu.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98142

Source reference: /cveMetadata/cveId

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No explicit severity was provided.

Event
#38235 · Revision 1
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