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Vulnerability record · CVE-2026-39386 · published 21 April 2026

CVE-2026-39386: M1k1o neko improper input validation vulnerability

MM1k1o · Neko

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.

8.8 CVSS 3.1 High EPSS 0.64% · top 51.5% CWE-20 · Improper input validationCWE-269 · Improper privilege management
8.8CVSS 3.1 base score
0.64%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/m1k1o/neko/releases/tag/v3.0.11 Product
https://github.com/m1k1o/neko/releases/tag/v3.1.2 Product
https://github.com/m1k1o/neko/security/advisories/GHSA-2gw9-c2r2-f5qf MitigationVendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-39386), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.