CVE-2026-33044 — homeassistant
CVE-2026-33044 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 Map-card through malicious device name
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-2026-33044.
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
An authenticated party can add a malicious name to their device entity, allowing for Cross-Site Scripting attacks against anyone who can see a dashboard with a Map-card which includes that entity. It requires that the victim hovers over an information point (The lines or the dots representing that device's movement, as shown in the screenshot below, with the example showing a html-injection using <s> to strikethrough the text)
<img width="348" height="355" alt="image" src="https://github.com/user-attachments/assets/1af3ef33-3a72-4816-8ade-e6405aace176" />
This allows an authenticated user to execute JavaScript in the context of any other users accessing a dashboard.
Details
The vulnerability exists in the map-card by adding a malicious entity and having the property hours_to_show set.
See example below, with the malicious entity being Pixel 9 <s> Fold Robin {{7*7}}:
Map card with malicious device entity:
<img width="338" height="332" alt="image" src="https://github.com/user-attachments/assets/15229cc3-1b69-438c-9ee5-cbfa9483aec9" />
YAML-view of same card: <img width="338" height="198" alt="image" src="https://github.com/user-attachments/assets/cd579266-75c3-4cdf-9d08-1544a6887feb" />
This issue largely resembles the issue documented in: CVE-2025-62172, but with an entity which can be displayed in a Map, instead of in an energy-dashboard.
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/d240549e-f26c-4617-89d7-5480451ae5a3" />
- Add the entity to a map card, which has the "hours to show"-attribute set, to display movement history <img width="296" height="383" alt="image" src="https://github.com/user-attachments/assets/b2db55b6-3d4b-4ab0-91fe-fc26813ad5ff" />
(The left arrow showing the custom setting, and the right arrow showing a data point which needs to be hovered)
- The payload executes when hovering a data-point (here shown with an "alert(document.domain"-payload) <img width="504" height="118" alt="image" src="https://github.com/user-attachments/assets/9f24e1fe-949f-4fa5-9e4f-781828a1343b" />
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, as it requires a specific setup (map-card with attribute hours_to_show set, as this brings up the trail). It is interesting to note that any user who sets this attribute, will be highly likely to trigger the vulnerability through normal use. It also has no potential for being imported through seemingly innocent integrations and can only be set explicitly by another invited user, a device name, a cloud service or through social engineering. 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.
Suggested criticality: Medium
Credit: Robin Lunde - https://robinlunde.com
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | homeassistant | ≥ 2020.02&&< 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-2026-33044 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-2026-33044 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33044. 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-2026-33044 in your dependencies?
O3 Security finds CVE-2026-33044 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.