Vulnerability-Lookup

GHSA-8FH7-QQ2H-XHH6

Vulnerability from github – Published: 2026-09-25 12:31 – Updated: 2026-09-25 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

fbdev: vfb: defer cleanup until the last reference

FBIOGETCMAP takes a shallow snapshot of info->cmap and performs the usercopy after dropping info->lock. vfb_remove() frees the colormap immediately after unregistering the framebuffer, even when an open file still holds a reference to fb_info. A concurrent driver unbind can therefore free the colormap while the ioctl copies it to userspace.

KASAN reports:

BUG: KASAN: slab-use-after-free in _copy_to_user Read of size 512 by task poc/125

_copy_to_user (./include/linux/instrumented.h:129 ./include/linux/uaccess.h:201 lib/usercopy.c:24) fb_cmap_to_user (./include/linux/uaccess.h:230 drivers/video/fbdev/core/fbcmap.c:211) do_fb_ioctl (drivers/video/fbdev/core/fb_chrdev.c:114)

Allocated by task 1: fb_alloc_cmap_gfp (./include/linux/slab.h:973 ./include/linux/slab.h:1290 drivers/video/fbdev/core/fbcmap.c:108) vfb_probe (drivers/video/fbdev/vfb.c:459)

Freed by task 124: fb_dealloc_cmap (drivers/video/fbdev/core/fbcmap.c:151) vfb_remove (drivers/video/fbdev/vfb.c:489)

unregister_framebuffer() drops the registration reference, and fbdev calls fb_destroy after the last put_fb_info(). Move the registered framebuffer's cleanup into an fb_destroy callback so its colormap and screen buffer stay alive until all file references have been released.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-97604"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-25T11:17:14Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: vfb: defer cleanup until the last reference\n\nFBIOGETCMAP takes a shallow snapshot of info-\u003ecmap and performs the\nusercopy after dropping info-\u003elock. vfb_remove() frees the colormap\nimmediately after unregistering the framebuffer, even when an open file\nstill holds a reference to fb_info. A concurrent driver unbind can\ntherefore free the colormap while the ioctl copies it to userspace.\n\nKASAN reports:\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user\n  Read of size 512 by task poc/125\n\n   _copy_to_user (./include/linux/instrumented.h:129 ./include/linux/uaccess.h:201 lib/usercopy.c:24)\n   fb_cmap_to_user (./include/linux/uaccess.h:230 drivers/video/fbdev/core/fbcmap.c:211)\n   do_fb_ioctl (drivers/video/fbdev/core/fb_chrdev.c:114)\n\n   Allocated by task 1:\n   fb_alloc_cmap_gfp (./include/linux/slab.h:973 ./include/linux/slab.h:1290 drivers/video/fbdev/core/fbcmap.c:108)\n   vfb_probe (drivers/video/fbdev/vfb.c:459)\n\n   Freed by task 124:\n   fb_dealloc_cmap (drivers/video/fbdev/core/fbcmap.c:151)\n   vfb_remove (drivers/video/fbdev/vfb.c:489)\n\nunregister_framebuffer() drops the registration reference, and fbdev calls\nfb_destroy after the last put_fb_info(). Move the registered framebuffer\u0027s\ncleanup into an fb_destroy callback so its colormap and screen buffer stay\nalive until all file references have been released.",
  "id": "GHSA-8fh7-qq2h-xhh6",
  "modified": "2026-09-25T12:31:26Z",
  "published": "2026-09-25T12:31:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97604"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3c91e51a53cf805e551e5dc8149cd0539a6dbb9d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5ff1effb047e465cde193d7df95988aa1520035e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/86356f13598f59f5acb1754895747dcdaf65a254"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a0a34a40ed299c9c7cff6af163a5b883ee9d6d73"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-97604 (GCVE-0-2026-97604)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:22 – Updated: 2026-09-25 10:22

Title

fbdev: vfb: defer cleanup until the last reference

Summary

In the Linux kernel, the following vulnerability has been resolved: fbdev: vfb: defer cleanup until the last reference FBIOGETCMAP takes a shallow snapshot of info->cmap and performs the usercopy after dropping info->lock. vfb_remove() frees the colormap immediately after unregistering the framebuffer, even when an open file still holds a reference to fb_info. A concurrent driver unbind can therefore free the colormap while the ioctl copies it to userspace. KASAN reports: BUG: KASAN: slab-use-after-free in _copy_to_user Read of size 512 by task poc/125 _copy_to_user (./include/linux/instrumented.h:129 ./include/linux/uaccess.h:201 lib/usercopy.c:24) fb_cmap_to_user (./include/linux/uaccess.h:230 drivers/video/fbdev/core/fbcmap.c:211) do_fb_ioctl (drivers/video/fbdev/core/fb_chrdev.c:114) Allocated by task 1: fb_alloc_cmap_gfp (./include/linux/slab.h:973 ./include/linux/slab.h:1290 drivers/video/fbdev/core/fbcmap.c:108) vfb_probe (drivers/video/fbdev/vfb.c:459) Freed by task 124: fb_dealloc_cmap (drivers/video/fbdev/core/fbcmap.c:151) vfb_remove (drivers/video/fbdev/vfb.c:489) unregister_framebuffer() drops the registration reference, and fbdev calls fb_destroy after the last put_fb_info(). Move the registered framebuffer's cleanup into an fb_destroy callback so its colormap and screen buffer stay alive until all file references have been released.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/86356f13598f59f5a…
https://git.kernel.org/stable/c/5ff1effb047e465cd…
https://git.kernel.org/stable/c/3c91e51a53cf805e5…
https://git.kernel.org/stable/c/a0a34a40ed299c9c7…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 5e266e2e0e19532c1b8e2e2bff1eb6ccf42e478a , < 86356f13598f59f5acb1754895747dcdaf65a254 (git) Affected: 5e266e2e0e19532c1b8e2e2bff1eb6ccf42e478a , < 5ff1effb047e465cde193d7df95988aa1520035e (git) Affected: 5e266e2e0e19532c1b8e2e2bff1eb6ccf42e478a , < 3c91e51a53cf805e551e5dc8149cd0539a6dbb9d (git) Affected: 5e266e2e0e19532c1b8e2e2bff1eb6ccf42e478a , < a0a34a40ed299c9c7cff6af163a5b883ee9d6d73 (git)
Linux	Linux	Affected: 2.6.30 Unaffected: 0 , < 2.6.30 (semver) Unaffected: 6.12.111 , ≤ 6.12.* (semver) Unaffected: 6.18.53 , ≤ 6.18.* (semver) Unaffected: 7.2.7 , ≤ 7.2.* (semver) Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)

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        {
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          "programFiles": [
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                  "versionEndExcluding": "6.12.111",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: vfb: defer cleanup until the last reference\n\nFBIOGETCMAP takes a shallow snapshot of info-\u003ecmap and performs the\nusercopy after dropping info-\u003elock. vfb_remove() frees the colormap\nimmediately after unregistering the framebuffer, even when an open file\nstill holds a reference to fb_info. A concurrent driver unbind can\ntherefore free the colormap while the ioctl copies it to userspace.\n\nKASAN reports:\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user\n  Read of size 512 by task poc/125\n\n   _copy_to_user (./include/linux/instrumented.h:129 ./include/linux/uaccess.h:201 lib/usercopy.c:24)\n   fb_cmap_to_user (./include/linux/uaccess.h:230 drivers/video/fbdev/core/fbcmap.c:211)\n   do_fb_ioctl (drivers/video/fbdev/core/fb_chrdev.c:114)\n\n   Allocated by task 1:\n   fb_alloc_cmap_gfp (./include/linux/slab.h:973 ./include/linux/slab.h:1290 drivers/video/fbdev/core/fbcmap.c:108)\n   vfb_probe (drivers/video/fbdev/vfb.c:459)\n\n   Freed by task 124:\n   fb_dealloc_cmap (drivers/video/fbdev/core/fbcmap.c:151)\n   vfb_remove (drivers/video/fbdev/vfb.c:489)\n\nunregister_framebuffer() drops the registration reference, and fbdev calls\nfb_destroy after the last put_fb_info(). Move the registered framebuffer\u0027s\ncleanup into an fb_destroy callback so its colormap and screen buffer stay\nalive until all file references have been released."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T10:22:16.613Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/a0a34a40ed299c9c7cff6af163a5b883ee9d6d73"
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      "title": "fbdev: vfb: defer cleanup until the last reference",
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    "datePublished": "2026-09-25T10:22:16.613Z",
    "dateReserved": "2026-09-24T16:01:01.158Z",
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    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
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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.

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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-8FH7-QQ2H-XHH6

CVE-2026-97604 (GCVE-0-2026-97604)

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