FKIE_CVE-2026-53403

Vulnerability from fkie_nvd - Published: 2026-07-19 12:16 - Updated: 2026-07-20 07:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var info->var, a framebuffer's current mode, is expected to have a matching entry in info->modelist. var_to_display() relies on this and treats a failed fb_match_mode() as "This should not happen". fb_set_var() keeps it true by adding the mode to the list on every change, and do_register_framebuffer() does the same at registration. store_modes() replaces the modelist from userspace. fb_new_modelist() validates the new modes but does not check that info->var still has a match. It relies on fbcon_new_modelist() to re-point consoles, but that only handles consoles mapped to the framebuffer. With fbcon unbound there are none, so info->var is left describing a mode that is no longer in the list. A later console takeover runs var_to_display(), where fb_match_mode() returns NULL and leaves fb_display[i].mode NULL. fbcon_switch() passes it to display_to_var(), and fb_videomode_to_var() dereferences the NULL mode. Keep the current mode in the list in fb_new_modelist(), the same way fb_set_var() does.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0d8c7f21ad8529d5c181e61f86be35b887ae2e4d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1458a4d804550b7101e8bb02c1cb941088e4c0c7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7640b4f68acb54c2c4f6b4a8aee0e9849dacd929
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7f08fc10fa3d3366dc3af723970bd03d7d6d10e3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8707f02ac9f5f632039b60df2c9f3dc914709f72
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/88913059c77e171f44ba829282d42dde0d458811
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/eea16b6f805c0b1fb2f72f0f771088ea45356956
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/video/fbdev/core/fbmem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1458a4d804550b7101e8bb02c1cb941088e4c0c7",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "8707f02ac9f5f632039b60df2c9f3dc914709f72",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "0d8c7f21ad8529d5c181e61f86be35b887ae2e4d",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "7640b4f68acb54c2c4f6b4a8aee0e9849dacd929",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "eea16b6f805c0b1fb2f72f0f771088ea45356956",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "88913059c77e171f44ba829282d42dde0d458811",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "7f08fc10fa3d3366dc3af723970bd03d7d6d10e3",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/video/fbdev/core/fbmem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "lessThan": "2.6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.260",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.211",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.177",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.144",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-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\nfbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var\n\ninfo-\u003evar, a framebuffer\u0027s current mode, is expected to have a matching\nentry in info-\u003emodelist. var_to_display() relies on this and treats a\nfailed fb_match_mode() as \"This should not happen\". fb_set_var() keeps it\ntrue by adding the mode to the list on every change, and\ndo_register_framebuffer() does the same at registration.\n\nstore_modes() replaces the modelist from userspace. fb_new_modelist()\nvalidates the new modes but does not check that info-\u003evar still has a\nmatch. It relies on fbcon_new_modelist() to re-point consoles, but that\nonly handles consoles mapped to the framebuffer. With fbcon unbound there\nare none, so info-\u003evar is left describing a mode that is no longer in the\nlist.\n\nA later console takeover runs var_to_display(), where fb_match_mode()\nreturns NULL and leaves fb_display[i].mode NULL. fbcon_switch() passes it\nto display_to_var(), and fb_videomode_to_var() dereferences the NULL mode.\n\nKeep the current mode in the list in fb_new_modelist(), the same way\nfb_set_var() does."
    }
  ],
  "id": "CVE-2026-53403",
  "lastModified": "2026-07-20T07:16:38.150",
  "metrics": {},
  "published": "2026-07-19T12:16:51.510",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0d8c7f21ad8529d5c181e61f86be35b887ae2e4d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1458a4d804550b7101e8bb02c1cb941088e4c0c7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7640b4f68acb54c2c4f6b4a8aee0e9849dacd929"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7f08fc10fa3d3366dc3af723970bd03d7d6d10e3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8707f02ac9f5f632039b60df2c9f3dc914709f72"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/88913059c77e171f44ba829282d42dde0d458811"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/eea16b6f805c0b1fb2f72f0f771088ea45356956"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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