CVE-2020-24355

critical

Description

Zyxel VMG5313-B30B router on firmware 5.13(ABCJ.6)b3_1127, and possibly older versions of firmware are affected by insecure permissions which allows regular and other users to create new users with elevated privileges. This is done by changing "FirstIndex" field in JSON that is POST-ed during account creation. Similar may also be possible with account deletion.

References

https://www.zyxel.com/support/security_advisories.shtml

https://blog.somegeneric.ninja/Zyxel_VMG5153_B30B_part2

https://blog.somegeneric.ninja/Zyxel_VMG5153_B30B

Details

Source: Mitre, NVD

Published: 2020-09-02

Updated: 2026-06-17

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

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

Severity: Critical

EPSS

EPSS: 0.00367