# 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.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Sep 2026
- **Updated:** 27 Oct 2026
- **Also known as:** GHSA-8w6r-cph7-4j6v

## 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 (Incorrect Comparison)

## 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.

## Is CVE-2026-56101 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56101 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56101 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56101 exists.

Affected product: OpenBSD. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-56101/ (Markdown: https://insights.sbomify.com/CVE-2026-56101/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56101
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56101
- OSV: https://osv.dev/vulnerability/CVE-2026-56101

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56101/
Summaries are generated and may contain mistakes; the official description above is the record.