Medium · CVSS 6.0CVE-2026-56101

OpenBSD ieee80211_crypto_tkip.c TKIP MIC Countermeasure Logic Inversion DoSCVE-2026-56101

Answer in brief

CVE-2026-56101 records a Medium severity (CVSS 6.0) vulnerability in OpenBSD ieee80211_crypto_tkip.c TKIP MIC Countermeasure Logic Inversion DoS. The current sources do not mark it as known exploited. The current feed maps OpenBSD/OpenBSD (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 8, 2026Updated Sep 10, 2026Source checked Oct 24, 2026First seen by HOL Sep 8, 2026Material review Sep 10, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.0
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 6.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps OpenBSD/OpenBSD (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
OpenBSD/OpenBSDgeneric	>=0 <1ee99dfcc4ddc87afc6395d5d3094e9d2314fb5a	1ee99dfcc4ddc87afc6395d5d3094e9d2314fb5a

Recommended response

Check inventory. Check lockfiles and deployed manifests for OpenBSD/OpenBSD.
Review the reported fix. Update OpenBSD/OpenBSD to 1ee99dfcc4ddc87afc6395d5d3094e9d2314fb5a if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 8, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.