CVE-2021-4105 | Unauthenticated Remote Code Execution on COSLAT Firewall

Improper Handling of Parameters vulnerability in BG-TEK COSLAT Firewall allows Remote Code Inclusion. This issue affects COSLAT Firewall: from 5.24.0.R.20180630 before 5.24.0.R.20210727.

Published: 2023-02-24 Last update: 2026-05-18 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-4105 is rated Moderate Risk (58.2/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 0.86%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-4105

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.73% 0.86% +0.14%
2 2026-05-19 0.56% 0.73% +0.16%
3 2026-02-25 — 0.56% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-4105

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]

Weakness enumeration for CVE-2021-4105

GitHub Security Advisory for CVE-2021-4105

GHSA-gr7g-5rvj-cf96 · Severity: critical — Improper Handling of Parameters vulnerability in BG-TEK COSLAT Firewall allows Remote Code...

Affected software / configurations for CVE-2021-4105

Vendor Product Version Raw CPE
bg-tek coslat_bx5s1d3_firmware >= 5.24.0.r.20180630, < 5.24.0.r.20210727 cpe:2.3:o:bg-tek:coslat_bx5s1d3_firmware:*:*:*:*:*:*:*:*
bg-tek coslat_bx5s1d4_firmware >= 5.24.0.r.20180630, < 5.24.0.r.20210727 cpe:2.3:o:bg-tek:coslat_bx5s1d4_firmware:*:*:*:*:*:*:*:*
bg-tek coslat_bx5s1d5_firmware >= 5.24.0.r.20180630, < 5.24.0.r.20210727 cpe:2.3:o:bg-tek:coslat_bx5s1d5_firmware:*:*:*:*:*:*:*:*
bg-tek coslat_rm1ds1000_firmware >= 5.24.0.r.20180630, < 5.24.0.r.20210727 cpe:2.3:o:bg-tek:coslat_rm1ds1000_firmware:*:*:*:*:*:*:*:*
bg-tek coslat_rm2ds2000_firmware >= 5.24.0.r.20180630, < 5.24.0.r.20210727 cpe:2.3:o:bg-tek:coslat_rm2ds2000_firmware:*:*:*:*:*:*:*:*
bg-tek coslat_rm2s200_firmware >= 5.24.0.r.20180630, < 5.24.0.r.20210727 cpe:2.3:o:bg-tek:coslat_rm2s200_firmware:*:*:*:*:*:*:*:*
bg-tek coslat_rm3s300_firmware >= 5.24.0.r.20180630, < 5.24.0.r.20210727 cpe:2.3:o:bg-tek:coslat_rm3s300_firmware:*:*:*:*:*:*:*:*
bg-tek coslat_rm4s500_firmware >= 5.24.0.r.20180630, < 5.24.0.r.20210727 cpe:2.3:o:bg-tek:coslat_rm4s500_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-4105

cvelogic Threat Intelligence