CVE-2026-56101 OpenBSD ieee80211_crypto_tkip.c TKIP MIC Countermeasure Logic Inversion DoS
Unauthenticated attackers within RF range can cause denial of service by exploiting a logic inversion in TKIP MIC failure handling to deauthenticate stations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-56101?
CVE-2026-56101 is a medium-severity denial of service vulnerability in OpenBSD, published on 8 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-697
Which versions are affected by CVE-2026-56101?
How do I fix CVE-2026-56101?
No fix has been published for CVE-2026-56101 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-56101 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56101 exists.
Sources
Also known as GHSA-8w6r-cph7-4j6v.