CVE-2026-56101

Wireless service interruption via inverted MIC window check

Published Sep 8, 2026 · Updated Sep 10, 2026

Incorrect comparison in OpenBSD before commit 1ee99df allows physically proximate attackers to interrupt wireless service using TKIP frames. ieee80211_michael_mic_failure() returns when two MIC failures occur within 60 seconds and enters the countermeasure path only after that window expires. Exposure requires the non-default WPA1/TKIP configuration; an affected access point deauthenticates every TKIP station and blocks reassociation for up to 90 seconds.

CVSS severity6.0
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect comparison in OpenBSD before commit 1ee99df allows physically proximate attackers to interrupt wireless service using TKIP frames. ieee80211_michael_mic_failure() returns when two MIC failures occur within 60 seconds and enters the countermeasure path only after that window expires. Exposure requires the non-default WPA1/TKIP configuration; an affected access point deauthenticates every TKIP station and blocks reassociation for up to 90 seconds.

The record

CVE
CVE-2026-56101
Published
Sep 8, 2026
Updated
Sep 10, 2026
Vendor
OpenBSD Project
Product
OpenBSD
Classifications
CWE-697, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1ee99dfcc4ddc87afc6395d5d3094e9d2314fb5a

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

OpenBSD Project · OpenBSDversion=0 <1ee99dfcc4ddc87afc6395d5d3094e9d2314fb5a

Published CVSS scores

5.3VulnCheck CNACVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
6.0VulnCheck CNACVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-697Incorrect Comparison
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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