HostapdApplication · W1.fi

CVE-2019-5061

MEDIUM · 6.5 CVSS v3.1 Published 2019-12-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
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
An exploitable denial-of-service vulnerability exists in the hostapd 2.6, where an attacker could trigger AP to send IAPP location updates for stations, before the required authentication process has completed. This could lead to different denial of service scenarios, either by causing CAM table attacks, or by leading to traffic flapping if faking already existing clients in other nearby Aps of the same wireless infrastructure. An attacker can forge Authentication and Association Request packets to trigger this vulnerability.

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

hostapd 2.6 sends IAPP (Inter-Access Point Protocol) location updates for stations before authentication completes. An attacker can forge Authentication and Association Request packets to trigger premature IAPP updates, causing denial-of-service via CAM table attacks or traffic flapping between APs in the same wireless infrastructure.

MitigationUpgrade hostapd to version 2.7 or later which contains the fix for proper authentication state validation before IAPP updates. Network monitoring for anomalous IAPP traffic patterns can provide interim detection.

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
HostapdApplication
Affected:= 2.6

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 installed hostapd version
    Run 'hostapd -v' or 'hostapd --version' to retrieve the version number. On Linux systems, also check '/usr/sbin/hostapd -v' or consult the package manager (dpkg -l hostapd, rpm -qi hostapd).
    Affected if The version returned is exactly 2.6.
  2. Verify IAPP configuration in hostapd.conf
    Inspect the hostapd configuration file (typically at /etc/hostapd.conf or /etc/hostapd/hostapd.conf) and search for the 'iapp_interface' directive. This directive enables IAPP functionality.
    Affected if The configuration contains 'iapp_interface' pointing to an active interface, meaning IAPP is enabled.
  3. Confirm IAPP process is running
    Run 'ps aux | grep hostapd' to verify the hostapd process is active, then check network interfaces for IAPP multicast traffic on UDP port 3517 (the standard IAPP port). Use 'netstat -ulnp | grep 3517' or 'ss -ulnp | grep 3517'.
    Affected if hostapd is running and UDP port 3517 is open and listening for IAPP traffic.
  4. Inspect IAPP traffic for premature updates
    Capture IAPP packets on the network (tcpdump -i <interface> udp port 3517). Examine IAPP Location Update messages and check if they occur for stations that have not yet completed 802.11 authentication (check for Association Response or successful Authentication frames not yet received).
    Affected if IAPP Location Update packets are observed for MAC addresses that have not completed the full authentication/association handshake.

A system is affected if it runs hostapd version 2.6 with IAPP interface enabled and IAPP Location Update messages are being sent for stations that have not completed 802.11 authentication.

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

Upgrade hostapd to version 2.7 or later which contains the fix for proper authentication state validation before IAPP updates. Network monitoring for anomalous IAPP traffic patterns can provide interim detection.

Fix this in Hostapd Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2019-5061 in production — separate from our analysis above.

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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
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