Auth bypass in M1k1o Neko
CVE-2026-39386
Neko is a a self-hosted virtual browser that runs in Docker and uses WebRTC In versions 3.0.0 through 3.0.10 and 3.1.0 through 3.1.1, any authenticated user can immediately obtain full administrative control of the entire Neko instance (member management, room settings, broadcast control, session termination, etc.). This results in a complete compromise of the instance. The vulnerability has been patched in v3.0.11 and v3.1.2. If upgrading is not immediately possible, the following mitigations can reduce risk: Restrict access to trusted users only (avoid granting accounts to untrusted parties); ensure all user passwords are strong and only shared with trusted individuals; run the instance only when needed; avoid leaving it continuously exposed; place the instance behind authentication layers such as a reverse proxy with additional access controls; disable or restrict access to the /api/profile endpoint if feasible; and/or monitor for suspicious privilege changes or unexpected administrative actions. Note that these are temporary mitigations and do not fully eliminate the vulnerability. Upgrading is strongly recommended.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
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: 0.006 (48.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Affected products
- M1k1o Neko — versions >= 3.0.0, < 3.0.11, >= 3.1.0, < 3.1.2
Weakness classification (CWE)
References
- github.com/m1k1o/neko/security/advisories/GHSA-2gw9-c2r2-f5qf (Mitigation, Vendor Advisory)
- github.com/m1k1o/neko/releases/tag/v3.0.11 (Product)
- github.com/m1k1o/neko/releases/tag/v3.1.2 (Product)
Frequently asked questions
- What is CVE-2026-39386?
- CVE-2026-39386 is a high-severity vulnerability in M1k1o Neko, classified under Improper Input Validation. CVSS score: 8.8/10. Published 2026-04-21.
- How severe is CVE-2026-39386?
- High severity. CVSS v3 base score is 8.8 out of 10.