CVE-2021-29632

Kernel memory corruption via scrolling highlight buffer

Published Jan 18, 2022 · Updated Aug 3, 2024

Out-of-bounds write in FreeBSD 12.2 and 13.0 allows local users with console access to corrupt kernel memory while text scrolls. The vt(4) driver's highlight buffer mishandles its bounds during console scrolling, letting console data overwrite adjacent console structures or other kernel memory. Access to the system console is required, and the vendor bounds the reported consequence to system misbehavior rather than code execution.

CVSS severity7.5
High
EPSS probability0.85%
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 write in FreeBSD 12.2 and 13.0 allows local users with console access to corrupt kernel memory while text scrolls. The vt(4) driver's highlight buffer mishandles its bounds during console scrolling, letting console data overwrite adjacent console structures or other kernel memory. Access to the system console is required, and the vendor bounds the reported consequence to system misbehavior rather than code execution.

The record

CVE
CVE-2021-29632
Published
Jan 18, 2022
Updated
Aug 3, 2024
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 18, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=FreeBSD 13.0-RELEASE before p6, 12.2-RELEASE before p12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=FreeBSD 13.0-RELEASE before p6, 12.2-RELEASE before p12

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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