dbcve.org
Mac Os XOperating system · Apple

CVE-2016-1853

HIGH · 7.5 CVSS v3.0 Published 2016-05-20
Fix available
A fix is available. Upgrade to after 10.11.4 or later.
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
Tcl in Apple OS X before 10.11.5 allows remote attackers to obtain sensitive information by leveraging SSLv2 support.

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

Tcl in Apple OS X before 10.11.5 supports SSLv2, an obsolete and cryptographically weak protocol. Remote attackers can exploit SSLv2 known weaknesses (including weak cipher options and lack of integrity checking) to perform man-in-the-middle attacks or intercept encrypted communications, potentially obtaining sensitive information.

MitigationUpgrade to Apple OS X 10.11.5 or later, which contains the patched Tcl version with SSLv2 support disabled or removed. If SSL connectivity is required, ensure only TLS 1.1+ protocols are enabled.

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
Mac Os XOperating system
Affected:<= 10.11.4

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
None
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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. Check Mac OS X version
    Run 'sw_vers -productVersion' in Terminal
    Affected if The version is 10.11.4 or lower (10.11.4, 10.11.3, 10.11.2, etc.)
  2. Confirm Tcl installation
    Run 'which tclsh' or 'which wish' in Terminal to see if Tcl is present
    Affected if Tcl is installed on the system
  3. Check Tcl version
    Run 'tclsh -version' or 'tclsh' then 'info patchlevel'
    Affected if Tcl version is present and running on the affected OS version (10.11.4 or lower)
  4. Check for SSLv2 support in Tcl TLS package
    Inspect the Tcl TLS package configuration by running 'tclsh' then 'package require tls' and checking if SSLv2 ciphers are advertised or available
    Affected if The TLS package returns SSLv2 as an available or enabled protocol option

The system is affected if it runs Mac OS X 10.11.4 or earlier AND has Tcl installed with SSLv2 protocol support enabled in its TLS/SSL configuration.

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
Upgrade available Upgrade to a release after 10.11.4
Interim mitigation

Upgrade to Apple OS X 10.11.5 or later, which contains the patched Tcl version with SSLv2 support disabled or removed. If SSL connectivity is required, ensure only TLS 1.1+ protocols are enabled.

Fix this in Mac Os X Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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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-2016-1853 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