# CVE-2026-22211: TinyOS <= 2.1.2 Global Buffer Overflow in printfUART

> Attacker can trigger global buffer overflow in TinyOS printfUART, causing denial of service or information disclosure in ZigBee networks.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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:** 14 Jan 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-hwxm-rgw2-8633

## What is CVE-2026-22211?

CVE-2026-22211 is a medium-severity memory corruption vulnerability in TinyOS, published on 14 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

TinyOS versions up to and including 2.1.2 contain a global buffer overflow vulnerability in the printfUART formatted output implementation used within the ZigBee / IEEE 802.15.4 networking stack. The implementation formats output into a fixed-size global buffer and concatenates strings for %s format specifiers using strcat() without verifying remaining buffer capacity. When printfUART is invoked with a caller-controlled string longer than the available space, the unbounded sprintf/strcat sequence writes past the end of debugbuf, resulting in global memory corruption. This can cause denial of service, unintended behavior, or information disclosure via corrupted adjacent global state or UART output.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-22211?


## How do I fix CVE-2026-22211?

No fix has been published for CVE-2026-22211 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-22211 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-22211 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22211 and fix it if it is affected.

What it is: CVE-2026-22211 is a medium-severity memory corruption vulnerability in TinyOS, published on 14 Jan 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-2026-22211 exists.

Affected product: TinyOS. 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-2026-22211/ (Markdown: https://insights.sbomify.com/CVE-2026-22211/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22211
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22211
- OSV: https://osv.dev/vulnerability/CVE-2026-22211

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22211/
Summaries are generated and may contain mistakes; the official description above is the record.