CVE-2021-20596 - CVE House
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Status published High CVE-2021-20596

NULL Pointer Dereference in MELSEC-F Series FX3U-ENET firmware version 1.14...

Vulnerability Description

NULL Pointer Dereference in MELSEC-F Series FX3U-ENET firmware version 1.14 and prior, FX3U-ENET-L firmware version 1.14 and prior and FX3U-ENET-P502 firmware version 1.14 and prior allows a remote unauthenticated attacker to cause a DoS condition in communication by sending specially crafted packets. Control by MELSEC-F series PLC is not affected and system reset is required for recovery.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

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Affected Vendor

Affected Software

MELSEC-F Series FX3U-ENET; FX3U-ENET-L; FX3U-ENET-P502
Vulnerable Versions:
Firmware version 1.14 and prior

Timeline

Official Publish: July 22nd, 2021
Last Modified: August 3rd, 2024
Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weaknesses (CWE)

No CWE data available

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.