CVE-2021-27420 | GE UR family input validation

GE UR firmware versions prior to version 8.1x web server task does not properly handle receipt of unsupported HTTP verbs, resulting in the web server becoming temporarily unresponsive after receiving a series of unsupported HTTP requests. When unresponsive, the web server is inaccessible. By itself, this is not particularly significant as the relay remains effective in all other functionality and communication channels.

Published: 2022-03-23 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-27420 is rated Moderate Risk (42.5/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.02%). 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-2021-27420

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 0.23% 1.02% +0.79%
2 2026-03-18 0.29% 0.23% -0.06%
3 2025-11-21 — 0.29% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-27420

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-27420

Affected software / configurations for CVE-2021-27420

Vendor Product Version Raw CPE
ge multilin_b30_firmware < 8.10 cpe:2.3:o:ge:multilin_b30_firmware:*:*:*:*:*:*:*:*
ge multilin_b90_firmware < 8.10 cpe:2.3:o:ge:multilin_b90_firmware:*:*:*:*:*:*:*:*
ge multilin_c60_firmware < 8.10 cpe:2.3:o:ge:multilin_c60_firmware:*:*:*:*:*:*:*:*
ge multilin_c70_firmware < 8.10 cpe:2.3:o:ge:multilin_c70_firmware:*:*:*:*:*:*:*:*
ge multilin_c95_firmware < 8.10 cpe:2.3:o:ge:multilin_c95_firmware:*:*:*:*:*:*:*:*
ge multilin_d30_firmware < 8.10 cpe:2.3:o:ge:multilin_d30_firmware:*:*:*:*:*:*:*:*
ge multilin_d60_firmware < 8.10 cpe:2.3:o:ge:multilin_d60_firmware:*:*:*:*:*:*:*:*
ge multilin_f35_firmware < 8.10 cpe:2.3:o:ge:multilin_f35_firmware:*:*:*:*:*:*:*:*
ge multilin_f60_firmware < 8.10 cpe:2.3:o:ge:multilin_f60_firmware:*:*:*:*:*:*:*:*
ge multilin_g30_firmware < 8.10 cpe:2.3:o:ge:multilin_g30_firmware:*:*:*:*:*:*:*:*
ge multilin_g60_firmware < 8.10 cpe:2.3:o:ge:multilin_g60_firmware:*:*:*:*:*:*:*:*
ge multilin_l30_firmware < 8.10 cpe:2.3:o:ge:multilin_l30_firmware:*:*:*:*:*:*:*:*
ge multilin_l60_firmware < 8.10 cpe:2.3:o:ge:multilin_l60_firmware:*:*:*:*:*:*:*:*
ge multilin_l90_firmware < 8.10 cpe:2.3:o:ge:multilin_l90_firmware:*:*:*:*:*:*:*:*
ge multilin_m60_firmware < 8.10 cpe:2.3:o:ge:multilin_m60_firmware:*:*:*:*:*:*:*:*
ge multilin_n60_firmware < 8.10 cpe:2.3:o:ge:multilin_n60_firmware:*:*:*:*:*:*:*:*
ge multilin_t35_firmware < 8.10 cpe:2.3:o:ge:multilin_t35_firmware:*:*:*:*:*:*:*:*
ge multilin_t60_firmware < 8.10 cpe:2.3:o:ge:multilin_t60_firmware:*:*:*:*:*:*:*:*
ge multilin_c30_firmware < 8.10 cpe:2.3:o:ge:multilin_c30_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-27420

URL Tags
https://www.cisa.gov/uscert/ics/advisories/icsa-21-075-02 Mitigation Third Party Advisory US Government Resource
https://www.gegridsolutions.com/Passport/Login.aspx Permissions Required Vendor Advisory
cvelogic Threat Intelligence