RCE in Lawnchair

CVE-2026-39866

Lawnchair is a free, open-source home app for Android. Prior to commit fcba413f55dd47f8a3921445252849126c6266b2, command injection in release_update.yml workflow dispatch input allows arbitrary code execution. Commit fcba413f55dd47f8a3921445252849126c6266b2 patches the issue.

Vulnerability class: Command Injection (OS Command Injection)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.030 (86.7th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 87th percentile — 86.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-39866: rose from 0.023 to 0.030.

EPSS over last 30 days · oldest: 0.023 · newest: 0.030 · change: +0.006

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-39866?
CVE-2026-39866 is a high-severity vulnerability in Lawnchair, classified under Command Injection. CVSS score: 8.8/10. Published 2026-04-21.
How severe is CVE-2026-39866?
High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2026-39866 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.