Is CVE-2021-27420 actively exploited?

No active exploitation of CVE-2021-27420 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-27420 be exploited remotely?

Yes. CVE-2021-27420 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-27420?

CVE-2021-27420 has a CVSS score of 5.3 (MEDIUM).

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MEDIUM

CVE-2021-27420

CWE-20Published: March 23, 2022· Updated: Jun 17, 2026

5.3

CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2021-27420 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges Req.None

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

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

Affected Vendors & Products

ge38 product(s)

multilin b30 firmwaremultilin b30multilin b90 firmwaremultilin b90multilin c60 firmwaremultilin c60multilin c70 firmwaremultilin c70multilin c95 firmwaremultilin c95multilin d30 firmwaremultilin d30+26

Source: NVD CPE · 38 total CPE entries