Vulnerability-Lookup

GHSA-PPQM-P5H9-4X92

Vulnerability from github – Published: 2026-08-27 06:31 – Updated: 2026-08-27 06:31

Details

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

fbdev: clear fb_info->mode before deleting a videomode

fb_set_var() can delete a mode from info->modelist when userspace passes FB_ACTIVATE_INV_MODE through FBIOPUT_VSCREENINFO. The code checks that the mode being deleted is not the current info->var and that fbcon is not using it, but it does not check fb_info->mode.

fb_info->mode may still point into the modelist entry being deleted. If the entry is freed, later mode sysfs reads through show_mode() can dereference a stale pointer.

Clear fb_info->mode before calling fb_delete_videomode() when it matches the mode being removed.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80579"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-26T15:17:14Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: clear fb_info-\u003emode before deleting a videomode\n\nfb_set_var() can delete a mode from info-\u003emodelist when userspace\npasses FB_ACTIVATE_INV_MODE through FBIOPUT_VSCREENINFO. The code\nchecks that the mode being deleted is not the current info-\u003evar and\nthat fbcon is not using it, but it does not check fb_info-\u003emode.\n\nfb_info-\u003emode may still point into the modelist entry being deleted.\nIf the entry is freed, later mode sysfs reads through show_mode() can\ndereference a stale pointer.\n\nClear fb_info-\u003emode before calling fb_delete_videomode() when it\nmatches the mode being removed.",
  "id": "GHSA-ppqm-p5h9-4x92",
  "modified": "2026-08-27T06:31:33Z",
  "published": "2026-08-27T06:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80579"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/95e647d2a5304a8fd11f1ba3c8502de700650131"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ce7fef961c63229b22dec415fb988899f479d61f"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-80579 (GCVE-0-2026-80579)

Vulnerability from cvelistv5 – Published: 2026-08-26 14:37 – Updated: 2026-08-27 05:02

Title

fbdev: clear fb_info->mode before deleting a videomode

Summary

In the Linux kernel, the following vulnerability has been resolved: fbdev: clear fb_info->mode before deleting a videomode fb_set_var() can delete a mode from info->modelist when userspace passes FB_ACTIVATE_INV_MODE through FBIOPUT_VSCREENINFO. The code checks that the mode being deleted is not the current info->var and that fbcon is not using it, but it does not check fb_info->mode. fb_info->mode may still point into the modelist entry being deleted. If the entry is freed, later mode sysfs reads through show_mode() can dereference a stale pointer. Clear fb_info->mode before calling fb_delete_videomode() when it matches the mode being removed.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/ce7fef961c63229b2…
https://git.kernel.org/stable/c/95e647d2a5304a8fd…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < ce7fef961c63229b22dec415fb988899f479d61f (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 95e647d2a5304a8fd11f1ba3c8502de700650131 (git)
Linux	Linux	Affected: 2.6.12 Unaffected: 0 , < 2.6.12 (semver) Unaffected: 7.1.10 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "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": "ce7fef961c63229b22dec415fb988899f479d61f",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "95e647d2a5304a8fd11f1ba3c8502de700650131",
              "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": "7.1.*",
              "status": "unaffected",
              "version": "7.1.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.10",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: clear fb_info-\u003emode before deleting a videomode\n\nfb_set_var() can delete a mode from info-\u003emodelist when userspace\npasses FB_ACTIVATE_INV_MODE through FBIOPUT_VSCREENINFO. The code\nchecks that the mode being deleted is not the current info-\u003evar and\nthat fbcon is not using it, but it does not check fb_info-\u003emode.\n\nfb_info-\u003emode may still point into the modelist entry being deleted.\nIf the entry is freed, later mode sysfs reads through show_mode() can\ndereference a stale pointer.\n\nClear fb_info-\u003emode before calling fb_delete_videomode() when it\nmatches the mode being removed."
        }
      ],
      "metrics": [
        {
          "cvssV3_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",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only through local framebuffer interfaces\u2014FBIOPUT_VSCREENINFO ioctl on /dev/fb* to delete a videomode and sysfs reads of /sys/class/graphics/fb*/mode via show_mode(); fbdev core has no network, Bluetooth, or remote packet path.\nAC:L - Exploitation is a deterministic state bug, not a race: ioctl with FB_ACTIVATE_INV_MODE frees the modelist kmalloc entry while fb_info-\u003emode still points into it, and a subsequent sysfs mode read reliably dereferences the stale pointer without attacker-uncontrollable timing.\nPR:L - The freeing trigger is FBIOPUT_VSCREENINFO on /dev/fb*, which requires only local framebuffer device access (video group or kiosk/embedded/HMI service accounts), not init-namespace root; sysfs mode reads are world-readable and complete the UAF disclosure path.\nUI:N - No victim interaction is required; the attacker performs ioctl mode deletion and sysfs mode reads through their own local process without needing another user to mount, open, or configure unrelated resources.\nS:U - The use-after-free corrupts kernel heap state within the local fbdev subsystem and does not cross VM, container, or IOMMU boundaries to impact resources under a different security authority.\nC:H - After fb_delete_videomode() kfree()s the fb_modelist object, show_mode()/mode_string() reads flag, vmode, xres, yres, and refresh from freed slab memory and copies attacker-influenced bytes to userspace\u2014a UAF information-disclosure primitive.\nI:H - The dangling fb_info-\u003emode pointer into a freed kmalloc object enables classic heap grooming between ioctl free and sysfs read; reallocated slab contents can be corrupted or confused for control-flow or arbitrary-write primitives beyond the immediate read.\nA:H - Dereferencing the freed fb_videomode structure causes KASAN-detectable use-after-free faults and kernel oops/panic on display-equipped embedded, automotive, kiosk, and console systems running the framebuffer subsystem."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T05:02:00.629Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/ce7fef961c63229b22dec415fb988899f479d61f"
        },
        {
          "url": "https://git.kernel.org/stable/c/95e647d2a5304a8fd11f1ba3c8502de700650131"
        }
      ],
      "title": "fbdev: clear fb_info-\u003emode before deleting a videomode",
      "x_generator": {
        "engine": "bippy-1.2.0"
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80579",
    "datePublished": "2026-08-26T14:37:37.320Z",
    "dateReserved": "2026-08-26T14:34:25.769Z",
    "dateUpdated": "2026-08-27T05:02:00.629Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
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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