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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 20 Apr 2023. Known ransomware use
Debian LinuxOperating system · Debian

CVE-2017-7494

CRITICAL · 9.8 CVSS v3.1 Published 2017-05-30
Fix available
A fix is available. Upgrade to 4.4.0 / 4.4.14 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Ransomware High EPSS Public exploit Remotely reachable No privileges Zero-click Patch available

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
Samba since version 3.5.0 and before 4.6.4, 4.5.10 and 4.4.14 is vulnerable to remote code execution vulnerability, allowing a malicious client to upload a shared library to a writable share, and then cause the server to load and execute it.

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

A remote code execution vulnerability in Samba allows an authenticated attacker with write access to a shared folder to upload a malicious shared library (.so file) and trick the server into loading and executing it. The flaw exists because the server does not properly validate paths in the is_known_pipename() function.

MitigationUpgrade Samba to version 4.6.4, 4.5.10, or 4.4.14 or later. Additionally, restrict write permissions on shares and disable anonymous access to limit exposure.

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
Debian LinuxOperating system
Affected:= 8.0
SambaApplication
Affected:>= 3.5.0, < 4.4.0>= 4.4.0, < 4.4.14>= 4.5.0, < 4.5.10>= 4.6.0, < 4.6.4

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. Check installed Samba version
    Run `smbd --version` or `rpm -q samba` (RHEL/CentOS) or `dpkg -l samba` (Debian)
    Affected if Version is 3.5.0 or higher but below 4.4.14, 4.5.10, or 4.6.4
  2. Verify Samba service is running
    Run `systemctl status smbd` or `service smb status`
    Affected if The smbd service is active and listening on ports 445/139
  3. Identify writable shares
    Run `smbclient -L localhost -U%` to list shares, then inspect /etc/samba/smb.conf for shares with `writeable = yes` or `read only = no`
    Affected if Any share is configured as writable (writeable = yes or read only = no)
  4. Confirm NT pipe support is enabled
    Check /etc/samba/smb.conf for the `nt pipe support = yes` setting (this is the default)
    Affected if `nt pipe support` is not explicitly set to `no` (default allows exploitation)

A system is affected if it runs a vulnerable Samba version (3.5.0 to 4.4.13, 4.5.0 to 4.5.9, or 4.6.0 to 4.6.3), has the Samba service active, and exposes at least one writable share with NT pipe support enabled.

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 4.4.0 / 4.4.14 / 4.5.10 or later
Fixed in 4.4.04.4.144.5.10
Vendor patch www.samba.org →
Interim mitigation

Upgrade Samba to version 4.6.4, 4.5.10, or 4.4.14 or later. Additionally, restrict write permissions on shares and disable anonymous access to limit exposure.

Recommended fix High confidence

Samba 4.6.4 or later, 4.5.10 or later, or 4.4.14 or later (or Samba 4.7.0+)

  1. 1. Identify the current Samba version by running: smbd --version or dpkg -l | grep samba
  2. 2. For Debian 8.0, run: apt-get update && apt-get install samba (to apply available security updates)
  3. 3. If the package manager does not provide a fixed version, download and compile Samba 4.6.4, 4.5.10, or 4.4.14 (or later) from the official Samba website at https://www.samba.org/
  4. 4. After upgrading, restart the Samba services: systemctl restart smbd nmbd (or service smbd restart on older systems)
  5. 5. Verify the installed version matches or exceeds the fixed releases: smbd --version
  6. 6. Ensure the server is not configured with writeable shares exposed to untrusted users, as a defense-in-depth measure until the upgrade is complete
Caveat Upgrading Samba may require adjustments to configuration; test in a non-production environment first, particularly if migrating between major version branches

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

Fix this in Debian Linux Exploited in the wild — priority engagement
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,620
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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-2017-7494 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