CVE-2020-24355
Zyxel VMG5313-B30B router on firmware 5.13(ABCJ.6)b3_1127, and possibly older versions of...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2020-24355- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 10.0 High
AV:N/AC:L/Au:N/C:C/I:C/A:C - Weakness
- CWE-732
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2020-24355- Updated
- 2026-11-02
EUVDEUVD-2020-17089 No score
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.
- Record
EUVD-2020-17089- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-2f6p-fvp2-42p6 No score
Zyxel VMG5313-B30B router on firmware 5.13(ABCJ.6)b3_1127, and possibly older versions of...
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.
- Record
GHSA-2f6p-fvp2-42p6- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-24355 is a critical vulnerability (CVSS 9.8) in Zyxel Vmg5313-b30b Firmware, published September 2, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.18%, the 82nd percentile. No source names a fixed version.