CVE-2026-56101

OpenBSD ieee80211_crypto_tkip.c TKIP MIC Countermeasure Logic Inversion DoS

Published: Sep 8, 2026Updated: Sep 10, 2026 Sources: CVE List NVDCWE-697

5.3MEDIUM

Description

OpenBSD before commit 1ee99df contains an inverted comparison vulnerability in the ieee80211_michael_mic_failure() function within sys/net80211/ieee80211_crypto_tkip.c that allows unauthenticated attackers within RF range to trigger denial of service by sending two malformed TKIP frames separated by more than 60 seconds. Attackers can exploit the reversed TKIP MIC failure countermeasure window check to deauthenticate all associated TKIP stations and block reassociation for up to 90 seconds, while within-window MIC failures that should engage countermeasures are silently discarded, leaving key-recovery attempts undetected.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:AAttack Vector

Adjacent

AC:HAttack Complexity

High

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:NConfidentiality

None

I:NIntegrity

None

A:HAvailability

High

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Weaknesses

CWE-697

Affected Products

OpenBSD

oss-project·CA

OpenBSDOn-premOS

Operating Systems / unix-bsd

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

References

https://pop.argus-systems.ai/advisory/adv-209.html

pop.argus-systems.ai

https://github.com/openbsd/src/commit/1ee99dfcc4ddc87afc6395d5d3094e9d2314fb5a

github.com

https://www.vulncheck.com/advisories/openbsd-ieee80211-crypto-tkip-c-tkip-mic-countermeasure-logic-inversion-dos

vulncheck.com

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