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01 Record

CVE-2021-35031

A vulnerability in the TFTP client of Zyxel GS1900 series firmware, XGS1210 series firmware, and XGS1250 series firmware, which could allow an authenticated LAN user to execute arbitrary OS commands

MediumPUBLISHEDCNA: Zyxel
CNA base score6.8 CVSS v3.xCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

02 Description

A vulnerability in the TFTP client of Zyxel GS1900 series firmware, XGS1210 series firmware, and XGS1250 series firmware, which could allow an authenticated LAN user to execute arbitrary OS commands

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
0.47% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 41.0% of scored records. A rank, not a probability.
NVD base score
8.0 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2021-12-28 10:36Z4 YR AGO
Last updated
2024-08-04 00:33Z2 YR AGO
Reserved
2021-06-17
Assigning CNA
Zyxel
Record state
PUBLISHED
Severity
Medium (CVSS 6.8)
CNA CVSS vector
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Weaknesses
  • CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')Base
Data version
5.1
Document digest
3e7e282ef504dd9d1a98071c0004caa3cc52bff8f87fba3a67d863da786c9fe1

05 Affected products

VendorProductVersionsPlatforms
ZyxelXGS1210 series firmware1.00(ABTY.4)C0—
ZyxelXGS1250 series firmware1.00(ABWE.0)C0—

06 References