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
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
Credits
Spike Reply Cybersecurity Team
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.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2024-27287 has a CVSS score of 6.5 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2024.2.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2024-27287? CVE-2024-27287 is a medium-severity cross-site scripting (XSS) vulnerability in esphome (pip), affecting versions >= 2023.12.9, < 2024.2.2. It is fixed in 2024.2.2. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2024-27287? CVE-2024-27287 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of esphome are affected by CVE-2024-27287? esphome (pip) versions >= 2023.12.9, < 2024.2.2 is affected.
- Is there a fix for CVE-2024-27287? Yes. CVE-2024-27287 is fixed in 2024.2.2. Upgrade to this version or later.
- Is CVE-2024-27287 exploitable, and should I be worried? Whether CVE-2024-27287 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-27287 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-27287? Upgrade
esphometo 2024.2.2 or later.