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TI-2026-40491 Aliases CVE-2026-56101GHSA-8w6r-cph7-4j6v

OpenBSD ieee80211_crypto_tkip.c TKIP MIC Countermeasure Logic Inversion DoS

Priority MEDIUM 60CWE-697Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00605 49th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Fixed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

No affected products listed by the sources yet.

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:openbsd:openbsd:*:*:*:*:*:*:*:*——OpenBSD
  • cpe:2.3:o:openbsd:openbsd:*:*:*:*:*:*:*:* Versions — — ·OpenBSD

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-56101
  2. 2026-10-03 Alias added: GHSA-8w6r-cph7-4j6v

References

Exploit 1

Patch 1

  • TI-2020-05854 smtp_mailaddr in smtp_session.c in OpenSMTPD 6.6, as used in OpenBSD 6.6 and other… KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-19792 The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently… CVSS 3.1CRITICAL 9.8
  • TI-2002-00376 Integer overflow in xdr_array function in RPC servers for operating systems that use… CVSS 3.1CRITICAL 9.8
  • TI-2024-05929 Openssh: regresshion - race condition in ssh allows rce/dos CVSS 3.1HIGH 8.1
  • TI-2003-00437 Off-by-one error in the fb_realpath() function, as derived from the realpath function in… CVSS 3.1CRITICAL 9.8
  • TI-2007-05153 Stack-based buffer overflow in the cons_options function in options.c in dhcpd in OpenBSD… CVSS 2.0HIGH 7.2
See all 369 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences