CVE-2026-33045 home-assistant CVE debrief

Who should care

Defenders responsible for Home Assistant installations, especially those using versions 2025.02 through 2025.12, should assess their exposure to this vulnerability and prioritize upgrading to version 2026.01 or later to mitigate the risk of cross-site scripting attacks.

Why it matters

CVE-2026-33045 is a cross-site scripting vulnerability in Home Assistant's 'remaining charge time' sensor for mobile phones, affecting versions 2025.02 through 2025.12. Defenders should verify exposure, prioritize upgrading to version 2026.01 or later, and monitor for potential exploitation attempts.

• Potential for unauthorized script execution in user browsers.
• Risk of data exposure or unauthorized actions due to XSS.
• Need for verification of affected version usage within the environment.
• Priority for timely upgrade to a fixed version.

Technical summary

The 'remaining charge time' sensor for mobile phones in Home Assistant, an open-source home automation software, is vulnerable to cross-site scripting (XSS). This vulnerability exists from version 2025.02 up to but not including version 2026.01. An attacker could exploit this vulnerability to execute malicious scripts in the context of a user's browser, potentially leading to unauthorized actions or data exposure. The issue is resolved in version 2026.01 of Home Assistant.

Defensive priority

Defenders should prioritize verifying exposure of Home Assistant installations to this XSS vulnerability, especially if versions 2025.02 through 2025.12 are in use, and ensure timely upgrade to version 2026.01 or later.

Recommended defensive actions

• Verify if Home Assistant versions 2025.02 through 2025.12 are in use and assess exposure to this XSS vulnerability.
• Prioritize upgrading affected Home Assistant installations to version 2026.01 or later.
• Monitor for potential exploitation attempts targeting this vulnerability.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its existence in versions 2025.02 through 2025.12 of Home Assistant and its fix in version 2026.01. Vendor advisories are available via GitHub.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.