What is CVE-2026-39880?

CVE-2026-39880 is a medium-severity vulnerability in Remnawave Backend, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 5.0/10. Published 2026-04-08.

How severe is CVE-2026-39880?

Medium severity. CVSS v3 base score is 5.0 out of 10.

Vulnerability in Remnawave Backend

CVE-2026-39880

Remnawave Backend is the backend for the Remnawave proxy and user management solution. Prior to 2.7.5, a glitch in the HWID device registration logic allows an authenticated user to bypass the configured limit for HWID devices and register…

Vulnerability class: Race Condition

EPSS: 0.000 (1.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N.

Affected products

Remnawave Backend — versions < 2.7.5

Weakness classification (CWE)

CWE-362 — Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

References

https://github.com/remnawave/backend/security/advisories/GHSA-985p-44h5-v3pq (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-39880?: CVE-2026-39880 is a medium-severity vulnerability in Remnawave Backend, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 5.0/10. Published 2026-04-08.
How severe is CVE-2026-39880?: Medium severity. CVSS v3 base score is 5.0 out of 10.