CVE-2020-24355
CVSS v3
9.8
CRITICAL
EPSS Score
2.2 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
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.
Technical details
- Published
- 2020-09-02
Frequently asked questions
What is CVE-2020-24355?
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.
Is CVE-2020-24355 actively exploited?
Active exploitation of CVE-2020-24355 has not been confirmed. Its EPSS score was 2.2% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2020-24355?
CVE-2020-24355 has a CVSS v3 base score of 9.8 (CRITICAL severity).
Is CVE-2020-24355 affecting your environment?
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