CVE-2026-64825: Home Assistant Core vulnerable to Path Traversal via backup upload during onboarding

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.6%, percentile 47: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 47% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes homeassistant (PyPI) < 2026.6.0, fixed in 2026.6.0. Check your lockfile, including transitive dependencies.

What it is

Home Assistant Core before 2026.6.0 contains a path traversal vulnerability that allows unauthenticated attackers to write arbitrary files to any directory on the host filesystem by uploading a crafted backup archive during the initial onboarding window. Attackers can manipulate the 'name' field inside the uploaded archive's backup.json to supply an absolute path, causing pathlib.Path.truediv to discard the configured backup directory prefix and write attacker-controlled content to arbitrary locations, with full filesystem access when the process runs as root.

From the GitHub advisory

Home Assistant Core before 2026.6.0 contains a path traversal vulnerability that allows unauthenticated attackers to write arbitrary files to any directory on the host filesystem by uploading a crafted backup archive during the initial onboarding window. Attackers can manipulate the 'name' field inside the uploaded archive's backup.json to supply an absolute path, causing pathlib.Path.truediv to discard the configured backup directory prefix and write attacker-controlled content to arbitrary locations, with full filesystem access when the process runs as root.

Weakness type: CWE-22.

Product: homeassistant (PyPI) · Assigned by: VulnCheck · Published: 2026-07-21

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: present (depends on deployment conditions)
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.58% probability of exploitation activity in the next 30 days; percentile 47.

Timeline

• 2026-07-21 — CVE record published by VulnCheck
• 2026-07-21 — GitHub-reviewed advisory GHSA-5hxg-r395-fqxx published (critical)
• 2026-10-08 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. Release Notes github.com
2. Patch Commit github.com

Vulnerability records

1. GitHub Advisory GHSA-5hxg-r395-fqxx github.com
2. CVE.org record CVE-2026-64825 cve.org
3. NVD entry CVE-2026-64825 nvd.nist.gov

Other references from the CVE record and advisory

1. Pull Request github.com
2. vulncheck.com vulncheck.com

Critical PyPI advisories · Today’s Security Digest