Vulnerability-Lookup

GHSA-28CJ-V8RJ-MQ63

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: bound mode sysfs output to the sysfs buffer

mode_string() uses snprintf() which can return a value larger than the remaining buffer space. show_modes() accumulates the return value into i without checking whether i has reached PAGE_SIZE, causing the offset to advance past the sysfs buffer if the modelist is long enough.

Add a size parameter to mode_string() and use scnprintf() to return only the bytes actually written. Add an early return when offset already exceeds the buffer. In show_modes(), stop accumulating once the buffer is full.

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-2026-80580"
  ],
  "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: bound mode sysfs output to the sysfs buffer\n\nmode_string() uses snprintf() which can return a value larger than the\nremaining buffer space. show_modes() accumulates the return value into i\nwithout checking whether i has reached PAGE_SIZE, causing the offset to\nadvance past the sysfs buffer if the modelist is long enough.\n\nAdd a size parameter to mode_string() and use scnprintf() to return\nonly the bytes actually written. Add an early return when offset\nalready exceeds the buffer. In show_modes(), stop accumulating once\nthe buffer is full.",
  "id": "GHSA-28cj-v8rj-mq63",
  "modified": "2026-08-27T06:31:33Z",
  "published": "2026-08-27T06:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80580"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/873a1aa15c313263f2e18b38cf525623cc4fabf6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d15d51fb26e830af58f3f21964f1c09c239077ea"
    }
  ],
  "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-2026-80580 (GCVE-0-2026-80580)

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

Title

fbdev: bound mode sysfs output to the sysfs buffer

Summary

In the Linux kernel, the following vulnerability has been resolved: fbdev: bound mode sysfs output to the sysfs buffer mode_string() uses snprintf() which can return a value larger than the remaining buffer space. show_modes() accumulates the return value into i without checking whether i has reached PAGE_SIZE, causing the offset to advance past the sysfs buffer if the modelist is long enough. Add a size parameter to mode_string() and use scnprintf() to return only the bytes actually written. Add an early return when offset already exceeds the buffer. In show_modes(), stop accumulating once the buffer is full.

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/873a1aa15c313263f…
https://git.kernel.org/stable/c/d15d51fb26e830af5…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 873a1aa15c313263f2e18b38cf525623cc4fabf6 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d15d51fb26e830af58f3f21964f1c09c239077ea (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/fbsysfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "873a1aa15c313263f2e18b38cf525623cc4fabf6",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "d15d51fb26e830af58f3f21964f1c09c239077ea",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/video/fbdev/core/fbsysfs.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: bound mode sysfs output to the sysfs buffer\n\nmode_string() uses snprintf() which can return a value larger than the\nremaining buffer space. show_modes() accumulates the return value into i\nwithout checking whether i has reached PAGE_SIZE, causing the offset to\nadvance past the sysfs buffer if the modelist is long enough.\n\nAdd a size parameter to mode_string() and use scnprintf() to return\nonly the bytes actually written. Add an early return when offset\nalready exceeds the buffer. In show_modes(), stop accumulating once\nthe buffer is full."
        }
      ],
      "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 by a local read(2) on /sys/class/graphics/fbN/modes, which flows through sysfs/kernfs into show_modes(); there is no network, adjacent-network, or physical-device packet path to this framebuffer sysfs handler.\nAC:L - Once the framebuffer modelist is long enough to fill PAGE_SIZE, snprintf\u0027s oversized return value deterministically pushes the offset past the buffer and subsequent writes use a wrapped huge size; an attacker can also grow the list via repeated FBIOPUT_VSCREENINFO or a privileged store_modes write.\nPR:L - The modes sysfs attribute is DEVICE_ATTR_RW with mode 0644, so any unprivileged local user can open and read it without capabilities; only populating an unusually long modelist may require root or membership in the video group for /dev/fb0 ioctl access.\nUI:N - Exploitation requires only the attacker reading the modes sysfs file themselves; no separate victim action such as mounting a filesystem or opening a file is needed.\nS:U - The overflow corrupts kernel heap memory within the same OS security boundary and can enable local privilege escalation, but it does not cross VM, IOMMU, or sandbox isolation boundaries.\nC:H - Writing past the PAGE_SIZE sysfs seq_file buffer is an out-of-bounds kernel heap write; once the offset exceeds PAGE_SIZE the remaining-length underflow gives snprintf an enormous size, corrupting adjacent kmalloc objects and enabling information disclosure.\nI:H - The unchecked offset advance causes repeated out-of-bounds writes into kernel heap memory beyond the sysfs buffer, a memory-corruption primitive that can be leveraged for arbitrary kernel writes or control-flow hijacking.\nA:H - Corrupting heap objects adjacent to the sysfs read buffer can trigger immediate kernel oops/panic or later crashes when those objects are used, satisfying High availability impact for kernel memory corruption."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T05:02:01.683Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/873a1aa15c313263f2e18b38cf525623cc4fabf6"
        },
        {
          "url": "https://git.kernel.org/stable/c/d15d51fb26e830af58f3f21964f1c09c239077ea"
        }
      ],
      "title": "fbdev: bound mode sysfs output to the sysfs buffer",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80580",
    "datePublished": "2026-08-26T14:37:37.917Z",
    "dateReserved": "2026-08-26T14:34:25.769Z",
    "dateUpdated": "2026-08-27T05:02:01.683Z",
    "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.

Action not permitted

GHSA-28CJ-V8RJ-MQ63

CVE-2026-80580 (GCVE-0-2026-80580)

Tags

Sightings

Nomenclature