CVE-2026-33045 — homeassistant
CVE-2026-33045 is a Cross-site Scripting (XSS) vulnerability in homeassistant. A fix is available for homeassistant — see the affected versions and patch details below.
Home Assistant has stored XSS in history-graphs
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33045.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
homeassistantReal-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
The "remaining charge time"-sensor for mobile phones (imported/included from Android Auto it appears) is vulnerable to the same issue as CVE-2025-62172. <img width="431" height="334" alt="image" src="https://github.com/user-attachments/assets/84e0dfad-b986-4e84-ad0e-674c5da88582" /> This also indicates that any sensor showing their name in the history-graph, is likely to be vulnerable to this issue.
Details
Another entity was found which displays the same behavior as in this issue: CVE-2025-62172
The History-graph card will sometimes display the name of the entity it is displaying, when the graph is shown as a line with values on the x and y axis. This appears to be vulnerable to Cross-Site scripting (XSS) as it does not have any output escaping or sanitization.
The PoC in this instance only shows HTML-injection in the form of the <s> -tag being rendered as strike through, but the vulnerability also allows for injecting arbitrary tags which execute JavaScript, like the example given in the PoC description below.
PoC
- Register a new sensor (or device) or change the name of an existing one, which provides a location
- Change the name to something malicious, for example
test <img src=x onerror=alert(document.domain) />For a new entity, it should work when setting the name. For old entities, go here: <img width="1300" height="411" alt="image" src="https://github.com/user-attachments/assets/7dbd9afa-2f4b-4d03-9384-d57c53eaff5c" />
PS: the example pictures show changing the name of the device-tracker entity, which is wrong. Just change the name of the remaining charge time-sensor in order to validate this finding
-
Add a history graph card with the malicious sensor
<img width="696" height="474" alt="image" src="https://github.com/user-attachments/assets/3cda78e6-3db5-4075-8924-ab9fc5759082" /> -
Hover the graph for payload execution
<img width="343" height="196" alt="image" src="https://github.com/user-attachments/assets/99e56169-b06a-4c60-9343-510e5d74af12" />
Impact
The impact of this vulnerability is that a user can target other users of the system and perform account takeover through client side exploitation of XSS.
In the context of this system, I believe the vulnerability to be less impactful than the CVSS metric describes. It is not displayed anywhere by default, it is not natural to display this history graph, and it also has no potential for being imported through seemingly innocent integrations. It also appears to rely on having used/using Android Auto. Other devices which has the same sensor can trigger the same vulnerability, and I expect there to exists cloud-based devices that would enable a threat actor to deliver the payload remotely.
Credit: Robin Lunde - https://robinlunde.com
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | homeassistant | ≥ 2025.02&&< 2026.01 | 2026.01pip install --upgrade 'homeassistant==2026.01' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for homeassistant, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update homeassistant to 2026.01 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33045 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33045 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33045. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33045 in your dependencies?
O3 Security finds CVE-2026-33045 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.