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

Vulnerability from cvelistv5 – Published: 2026-08-26 14:37 – Updated: 2026-08-27 05:02
VLAI
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
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 873a1aa15c313263f2e18b38cf525623cc4fabf6 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d15d51fb26e830af58f3f21964f1c09c239077ea (git)
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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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          "programFiles": [
            "drivers/video/fbdev/core/fbsysfs.c"
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        }
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              "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."
            }
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      "providerMetadata": {
        "dateUpdated": "2026-08-27T05:02:01.683Z",
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    "datePublished": "2026-08-26T14:37:37.917Z",
    "dateReserved": "2026-08-26T14:34:25.769Z",
    "dateUpdated": "2026-08-27T05:02:01.683Z",
    "state": "PUBLISHED"
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        "descriptions": [
          {
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            "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."
          }
        ],
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        "lastModified": "2026-08-27T06:17:44.300",
        "metrics": {
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                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
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                "userInteraction": "NONE",
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "vulnStatus": "Received"
      }
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      "current_release_date": "2026-08-27T09:50:03+00:00",
      "cve": "CVE-2026-80580",
      "id": "CVE-2026-80580",
      "initial_release_date": "2026-08-26T00:00:00+00:00",
      "product_status:known_affected": "156",
      "product_status:known_not_affected": "118",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: fbdev: bound mode sysfs output to the sysfs buffer",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80580.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.



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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.