dbcve.org
FreeBSDOperating system

CVE-2021-29632

HIGH · 7.5 CVSS v3.1 Published 2022-01-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In FreeBSD 13.0-STABLE before n247428-9352de39c3dc, 12.2-STABLE before r370674, 13.0-RELEASE before p6, and 12.2-RELEASE before p12, certain conditions involving use of the highlight buffer while text is scrolling on the console, console data may overwrite data structures associated with the system console or other kernel memory.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Memory corruption vulnerability in FreeBSD's console subsystem where improper handling of the highlight buffer during text scrolling allows console data to overwrite kernel data structures, potentially enabling privilege escalation or denial of service.

MitigationApply FreeBSD security patches (p6 for 13.0-RELEASE, p12 for 12.2-RELEASE, or update stable branches past the specified revisions) to fix the highlight buffer handling in the console driver.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FreeBSDOperating system
Affected:= 12.2= 13.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify the operating system is FreeBSD
    Run 'uname -s' and confirm the output is 'FreeBSD'
    Affected if The OS is not FreeBSD (this CVE only affects FreeBSD)
  2. Check the installed FreeBSD version
    Run 'uname -r' or 'freebsd-version -k' to get the release version number
    Affected if The version is 12.2 or 13.0 (exact match to affected releases)
  3. Confirm the patch level for 13.0-RELEASE
    Check /usr/src/UPDATING or run 'freebsd-version -u' to see if patches are applied. Look for mention of p6 or later security patches
    Affected if Running 13.0-RELEASE without p6 or later patches applied
  4. Confirm the patch level for 12.2-RELEASE
    Check /usr/src/UPDATING or run 'freebsd-version -u' to see if patches are applied. Look for mention of p12 or later security patches
    Affected if Running 12.2-RELEASE without p12 or later patches applied
  5. Determine if console subsystem is in use
    Check if the system has active console sessions or if vt(4) or sc(4) console drivers are loaded: 'sysctl kern.vt' or 'kldstat | grep -E sc|vt'
    Affected if Console subsystem is active (vulnerable code path is triggered during text scrolling operations)

Affected if running FreeBSD 12.2 without p12+ patches or FreeBSD 13.0 without p6+ patches, and the console subsystem is in active use

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply FreeBSD security patches (p6 for 13.0-RELEASE, p12 for 12.2-RELEASE, or update stable branches past the specified revisions) to fix the highlight buffer handling in the console driver.

Recommended fix High confidence

FreeBSD 12.2-RELEASE-p12 or later; FreeBSD 13.0-RELEASE-p6 or later

  1. Upgrade FreeBSD 12.2-RELEASE to version 12.2-RELEASE-p12 or later
  2. Upgrade FreeBSD 13.0-RELEASE to version 13.0-RELEASE-p6 or later
  3. If running STABLE branches, update to a version after r370674 (12.2-STABLE) or after n247428-9352de39c3dc (13.0-STABLE)
  4. Reboot the system after applying the update to ensure the kernel patch takes effect
  5. Verify the fix by checking freebsd-version -u or uname -a shows the patched version
Caveat FreeBSD patch releases are cumulative and contain only security fixes; no breaking changes expected

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in FreeBSD Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-29632 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data