CVE-2021-47383

Kernel memory corruption via incomplete framebuffer state

Published May 21, 2024 · Updated Aug 5, 2026

Out-of-bounds access in affected Linux kernel releases allows local users to corrupt kernel memory through a crafted framebuffer ioctl. When vc_resize skips resize_screen for an unchanged request, fb_var_screeninfo remains incomplete and updatescrollmode derives an invalid row count used by imageblit. Access to a framebuffer device is required; successful triggering can disclose or corrupt kernel memory and crash the host.

CVSS severity7.8
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in affected Linux kernel releases allows local users to corrupt kernel memory through a crafted framebuffer ioctl. When vc_resize skips resize_screen for an unchanged request, fb_var_screeninfo remains incomplete and updatescrollmode derives an invalid row count used by imageblit. Access to a framebuffer device is required; successful triggering can disclose or corrupt kernel memory and crash the host.

The record

CVE
CVE-2021-47383
Published
May 21, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <067c694d06040db6f0c65281bb358452ca6d85b9
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3b0c406124719b625b1aba431659f5cdc24a982c
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <699d926585daa6ec44be556cdc1ab89e5d54557b
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <70aed03b1d5a5df974f456cdc8eedb213c94bb8b
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7e71fcedfda6f7de18f850a6b36e78d78b04476f
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <883f7897a25e3ce14a7f274ca4c73f49ac84002a
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8a6a240f52e14356386030d8958ae8b1761d2325
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d570c48dd37dbe8fc6875d4461d01a9554ae2560
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <067c694d06040db6f0c65281bb358452ca6d85b9; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3b0c406124719b625b1aba431659f5cdc24a982c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <699d926585daa6ec44be556cdc1ab89e5d54557b; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <70aed03b1d5a5df974f456cdc8eedb213c94bb8b; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7e71fcedfda6f7de18f850a6b36e78d78b04476f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <883f7897a25e3ce14a7f274ca4c73f49ac84002a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8a6a240f52e14356386030d8958ae8b1761d2325; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d570c48dd37dbe8fc6875d4461d01a9554ae2560; version=2.6.12

Published CVSS scores

7.1UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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