Improper Certificate ValidationWeakness · CWE-295

CVE-2026-38974

MEDIUM · 5.3 CVSS v3.1 Published 2026-07-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click 5 weeks old

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
Dulwich through 1.1.0 was found to be missing SSH host key verification in contrib/paramiko_vendor.py.

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

Dulwich, a Python Git implementation, lacks SSH host key verification in its paramiko_vendor.py module. This allows man-in-the-middle attacks where an attacker can intercept SSH connections by presenting a rogue SSH server, since the client does not verify the server's host key before establishing the connection.

MitigationEnable host key verification in SSH connections or upgrade to a patched version of Dulwich that implements proper host key validation in paramiko_vendor.py.

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

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
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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. Identify Dulwich installation and version
    Run 'pip show dulwich' or check your package manager to determine the installed version of Dulwich
    Affected if The installed version falls within or below the unpatched version range (compare to the latest patched version)
  2. Verify paramiko_vendor.py is in use
    Check if your Dulwich configuration or codebase imports and uses the paramiko_vendor.py module for SSH operations (look for 'from dulwich.contrib import paramiko_vendor' or similar imports)
    Affected if paramiko_vendor.py is being used for SSH transport in your Git operations
  3. Inspect paramiko_vendor.py for host key verification
    Examine the paramiko_vendor.py source file (typically in site-packages/dulwich/contrib/) for host key verification logic. Search for 'host_key' or 'verify_host_key' parameters in the SSHClient initialization
    Affected if Host key verification is not implemented or is explicitly disabled in the paramiko_vendor.py code
  4. Check for SSH connection configurations
    Review any Dulwich configuration files or application code that establishes SSH connections to Git remotes. Look for explicit host key verification settings
    Affected if SSH connections to Git remotes are configured without host key verification enabled

A user is affected if they use Dulwich for SSH Git operations with an unpatched version that lacks host key verification in paramiko_vendor.py, allowing potential interception of SSH connections.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Enable host key verification in SSH connections or upgrade to a patched version of Dulwich that implements proper host key validation in paramiko_vendor.py.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2026-38974 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
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