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HeimdalApplication · Heimdal Project

CVE-2022-44640

CRITICAL · 9.8 CVSS v3.1 Published 2022-12-25
Fix available
A fix is available. Upgrade to 4.15.3 / 4.16.8 or later.
See remediation →
100/100
Remediation priority · Urgent
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
Heimdal before 7.7.1 allows remote attackers to execute arbitrary code because of an invalid free in the ASN.1 codec used by the Key Distribution Center (KDC).

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

Heimdal Kerberos implementation before version 7.7.1 contains a memory corruption vulnerability in the ASN.1 codec used by the Key Distribution Center (KDC). The flaw is an invalid free operation during ASN.1 decoding that can be exploited by remote attackers to execute arbitrary code, likely via specially crafted Kerberos or PKI-related network traffic.

MitigationUpgrade Heimdal to version 7.7.1 or later to address the invalid free vulnerability in the ASN.1 codec. Given the KDC's critical role in Kerberos authentication and the CVSS 9.8 severity, priority patching is essential.

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
HeimdalApplication
Affected:< 7.7.1
SambaApplication
Affected:>= 4.15.0, < 4.15.3>= 4.16.0, < 4.16.8>= 4.17.0, < 4.17.4

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
High
Integrity
High
Availability
High

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

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. Determine installed Heimdal version
    Run 'heimdal --version' or check the package manager for heimdal (e.g., dpkg -l | grep heimdal, rpm -qa | grep heimdal)
    Affected if The reported version is earlier than 7.7.1
  2. Determine installed Samba version
    Run 'samba --version' or check the package manager for samba (e.g., dpkg -l | grep samba, rpm -qa | grep samba)
    Affected if The reported version falls within 4.15.0 to 4.15.2, 4.16.0 to 4.16.7, or 4.17.0 to 4.17.3
  3. Verify if KDC component is enabled
    Check for running KDC processes (e.g., 'ps aux | grep kdc' or 'systemctl list-units | grep kdc') or examine Kerberos configuration files for KDC settings
    Affected if A Heimdal or Samba KDC is actively running or configured to start, as the vulnerability resides in the ASN.1 codec used by the KDC
  4. Confirm Samba is using Heimdal KDC
    Examine Samba configuration (smb.conf) for 'kerberos method' or 'kdc' related settings, or check which KDC Samba is configured to use
    Affected if Samba is configured to use the Heimdal KDC rather than a separate Active Directory domain controller

You are affected if you are running Heimdal version earlier than 7.7.1 or a vulnerable Samba version (4.15.0-4.15.2, 4.16.0-4.16.7, or 4.17.0-4.17.3) with the KDC component enabled and using the Heimdal ASN.1 codec.

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
Upgrade available Upgrade to 4.15.3 / 4.16.8 / 4.17.4 or later
Fixed in 4.15.34.16.84.17.4
Interim mitigation

Upgrade Heimdal to version 7.7.1 or later to address the invalid free vulnerability in the ASN.1 codec. Given the KDC's critical role in Kerberos authentication and the CVSS 9.8 severity, priority patching is essential.

Recommended fix High confidence

Heimdal 7.7.1 or later; Samba 4.15.3, 4.16.8, or 4.17.4 (or later stable releases)

  1. 1. Identify whether the system runs Heimdal standalone or embeds it via Samba by checking installed packages or binaries (e.g., run 'heimdal --version' or 'samba --version')
  2. 2. For Heimdal installations: run 'heimdal --version' to confirm version is below 7.7.1, then upgrade to Heimdal 7.7.1 or later using the system's package manager or compile from source at https://github.com/heimdal/heimdal
  3. 3. For Samba installations: run 'samba --version' to confirm the installed version falls within the vulnerable ranges (4.15.0-4.15.2, 4.16.0-4.16.7, or 4.17.0-4.17.3)
  4. 4. Upgrade to the patched Samba version: 4.15.3, 4.16.8, or 4.17.4 (or later) via the distribution's package manager or compile from https://download.samba.org/pub/samba/
  5. 5. After upgrading, restart any services using the affected software (kdc for Heimdal, smbd/nmbd/winbindd for Samba)
  6. 6. Verify the new version is installed by re-running the version command

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

Fix this in Heimdal Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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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-2022-44640 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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