Vulnerability-Lookup

FKIE_CVE-2021-47383

Vulnerability from fkie_nvd - Published: 2024-05-21 15:15 - Updated: 2026-08-04 10:17

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: tty: Fix out-of-bound vmalloc access in imageblit This issue happens when a userspace program does an ioctl FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct containing only the fields xres, yres, and bits_per_pixel with values. If this struct is the same as the previous ioctl, the vc_resize() detects it and doesn't call the resize_screen(), leaving the fb_var_screeninfo incomplete. And this leads to the updatescrollmode() calculates a wrong value to fbcon_display->vrows, which makes the real_y() return a wrong value of y, and that value, eventually, causes the imageblit to access an out-of-bound address value. To solve this issue I made the resize_screen() be called even if the screen does not need any resizing, so it will "fix and fill" the fb_var_screeninfo independently.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/067c694d06040db6f0c65281bb358452ca6d85b9	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3b0c406124719b625b1aba431659f5cdc24a982c	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/699d926585daa6ec44be556cdc1ab89e5d54557b	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/70aed03b1d5a5df974f456cdc8eedb213c94bb8b	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/7e71fcedfda6f7de18f850a6b36e78d78b04476f	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/883f7897a25e3ce14a7f274ca4c73f49ac84002a	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/8a6a240f52e14356386030d8958ae8b1761d2325	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d570c48dd37dbe8fc6875d4461d01a9554ae2560	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/067c694d06040db6f0c65281bb358452ca6d85b9	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/3b0c406124719b625b1aba431659f5cdc24a982c	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/699d926585daa6ec44be556cdc1ab89e5d54557b	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/70aed03b1d5a5df974f456cdc8eedb213c94bb8b	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/7e71fcedfda6f7de18f850a6b36e78d78b04476f	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/883f7897a25e3ce14a7f274ca4c73f49ac84002a	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/8a6a240f52e14356386030d8958ae8b1761d2325	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/d570c48dd37dbe8fc6875d4461d01a9554ae2560	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*

JSON

To clipboard

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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntty: Fix out-of-bound vmalloc access in imageblit\n\nThis issue happens when a userspace program does an ioctl\nFBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct\ncontaining only the fields xres, yres, and bits_per_pixel\nwith values.\n\nIf this struct is the same as the previous ioctl, the\nvc_resize() detects it and doesn\u0027t call the resize_screen(),\nleaving the fb_var_screeninfo incomplete. And this leads to\nthe updatescrollmode() calculates a wrong value to\nfbcon_display-\u003evrows, which makes the real_y() return a\nwrong value of y, and that value, eventually, causes\nthe imageblit to access an out-of-bound address value.\n\nTo solve this issue I made the resize_screen() be called\neven if the screen does not need any resizing, so it will\n\"fix and fill\" the fb_var_screeninfo independently."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: tty: corrige el acceso vmalloc fuera de los l\u00edmites en imageblit. Este problema ocurre cuando un programa de espacio de usuario realiza un ioctl FBIOPUT_VSCREENINFO pasando la estructura fb_var_screeninfo que contiene solo los campos xres, yres y bits_per_pixel con valores. Si esta estructura es la misma que la ioctl anterior, vc_resize() la detecta y no llama a resize_screen(), dejando fb_var_screeninfo incompleto. Y esto lleva a que updatecrollmode() calcule un valor incorrecto para fbcon_display-\u0026gt;vrows, lo que hace que real_y() devuelva un valor incorrecto de y, y ese valor, eventualmente, hace que imageblit acceda a un valor de direcci\u00f3n fuera de los l\u00edmites. . Para resolver este problema, hice que se llamara a resize_screen() incluso si la pantalla no necesita ning\u00fan cambio de tama\u00f1o, por lo que \"arreglar\u00e1 y completar\u00e1\" fb_var_screeninfo de forma independiente."
    }
  ],
  "id": "CVE-2021-47383",
  "lastModified": "2026-08-04T10:17:00.893",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
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        "type": "Secondary"
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          "availabilityImpact": "HIGH",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
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        "source": "nvd@nist.gov",
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        "ssvcData": {
          "id": "CVE-2021-47383",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2024-06-17T17:37:20.634635Z",
          "version": "2.0.3"
        }
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    ]
  },
  "published": "2024-05-21T15:15:23.873",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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      "url": "https://git.kernel.org/stable/c/067c694d06040db6f0c65281bb358452ca6d85b9"
    },
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
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      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
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  ]
}

CVE-2021-47383 (GCVE-0-2021-47383)

Vulnerability from cvelistv5 – Published: 2024-05-21 15:03 – Updated: 2026-08-05 08:47

Title

tty: Fix out-of-bound vmalloc access in imageblit

Summary

Severity

7.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-06-17 17:37 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6641 records in the last 180 days details

References

8 references

URL	Tags
https://git.kernel.org/stable/c/7e71fcedfda6f7de1…
https://git.kernel.org/stable/c/70aed03b1d5a5df97…
https://git.kernel.org/stable/c/067c694d06040db6f…
https://git.kernel.org/stable/c/8a6a240f52e143563…
https://git.kernel.org/stable/c/883f7897a25e3ce14…
https://git.kernel.org/stable/c/d570c48dd37dbe8fc…
https://git.kernel.org/stable/c/699d926585daa6ec4…
https://git.kernel.org/stable/c/3b0c406124719b625…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 7e71fcedfda6f7de18f850a6b36e78d78b04476f (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 70aed03b1d5a5df974f456cdc8eedb213c94bb8b (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 067c694d06040db6f0c65281bb358452ca6d85b9 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 8a6a240f52e14356386030d8958ae8b1761d2325 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 883f7897a25e3ce14a7f274ca4c73f49ac84002a (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d570c48dd37dbe8fc6875d4461d01a9554ae2560 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 699d926585daa6ec44be556cdc1ab89e5d54557b (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 3b0c406124719b625b1aba431659f5cdc24a982c (git)
Linux	Linux	Affected: 2.6.12 Unaffected: 0 , < 2.6.12 (semver) Unaffected: 4.4.286 , ≤ 4.4.* (semver) Unaffected: 4.9.285 , ≤ 4.9.* (semver) Unaffected: 4.14.249 , ≤ 4.14.* (semver) Unaffected: 4.19.209 , ≤ 4.19.* (semver) Unaffected: 5.4.151 , ≤ 5.4.* (semver) Unaffected: 5.10.71 , ≤ 5.10.* (semver) Unaffected: 5.14.10 , ≤ 5.14.* (semver) Unaffected: 5.15 , ≤ * (original_commit_for_fix)

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      "title": "tty: Fix out-of-bound vmalloc access in imageblit",
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    "assignerShortName": "Linux",
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    "datePublished": "2024-05-21T15:03:44.286Z",
    "dateReserved": "2024-05-21T14:58:30.812Z",
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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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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.

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