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FreeBSDOperating system

CVE-2019-14899

HIGH · 7.4 CVSS v3.1 Published 2019-12-11
Fix available
A fix is available. Upgrade to 10.15.6 / 13.4.8 or later.
See remediation →
74/100
Remediation priority · Elevated

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
A vulnerability was discovered in Linux, FreeBSD, OpenBSD, MacOS, iOS, and Android that allows a malicious access point, or an adjacent user, to determine if a connected user is using a VPN, make positive inferences about the websites they are visiting, and determine the correct sequence and acknowledgement numbers in use, allowing the bad actor to inject data into the TCP stream. This provides everything that is needed for an attacker to hijack active connections inside the VPN tunnel.

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

This vulnerability allows a malicious access point or adjacent attacker to perform traffic analysis on VPN connections by observing packet timing, size patterns, and other heuristics to detect VPN usage, infer visited websites, and extract TCP sequence/acknowledgment numbers. With these values, the attacker can inject malicious data into the TCP stream and hijack active connections inside the VPN tunnel.

MitigationRemediation involves configuring strict firewall rules to force all traffic through the VPN tunnel, disabling IPv6 if not needed, or updating affected operating systems to versions that include proper network boundary enforcement between VPN interfaces and physical interfaces.

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:all versions
Linux KernelOperating system
Affected:all versions
OpenBSDOperating system
Affected:all versions
IpadosOperating system
Affected:< 13.6
Iphone OsOperating system
Affected:< 13.6
Mac Os XOperating system
Affected:< 10.15.6
macOSOperating system
Affected:= 11.0
TvosOperating system
Affected:< 13.4.8

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
Adjacent
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:L/UI:R/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. Identify your operating system and version
    Run 'uname -a' on Linux/FreeBSD, 'sw_vers' on macOS, or check Settings > General > About on iOS/tvOS
    Affected if The OS is FreeBSD, OpenBSD, Linux Kernel any version, or Apple iOS/iPadOS < 13.6, macOS < 10.15.6, macOS 11.0, or tvOS < 13.4.8
  2. Determine if a VPN client is installed and active
    Check for running VPN processes (ps aux | grep -i vpn) or active network interfaces (ip addr show or ifconfig) that indicate VPN tunnel adapters such as tun0, tap0, utun, or similar
    Affected if A VPN client is installed and an active VPN tunnel exists, exposing traffic to the vulnerability
  3. Verify VPN traffic isolation between physical and VPN interfaces
    Inspect firewall rules (iptables -L -v -n on Linux, pfctl -sr on OpenBSD/FreeBSD, or /usr/libexec/ApplicationFirewall/socketfilterfw --listapps on macOS) to see if all traffic is forced through the VPN interface and not leaking to the physical interface
    Affected if Firewall rules do not enforce strict boundary between VPN tunnel interface and physical network interface, allowing traffic analysis
  4. Check IPv6 configuration status
    Run 'ip -6 addr show' on Linux/FreeBSD or check Network Preferences on macOS/iOS to see if IPv6 is enabled on active network interfaces
    Affected if IPv6 is enabled and active on the system while using a VPN, providing an additional attack vector for traffic analysis

You are affected if your OS version matches the affected list AND you have an active VPN tunnel without strict firewall enforcement isolating VPN traffic from the physical interface.

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 10.15.6 / 13.4.8 / 13.6 or later
Fixed in 10.15.613.4.813.6
Interim mitigation

Remediation involves configuring strict firewall rules to force all traffic through the VPN tunnel, disabling IPv6 if not needed, or updating affected operating systems to versions that include proper network boundary enforcement between VPN interfaces and physical interfaces.

Fix this in FreeBSD Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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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-2019-14899 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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