Which products and versions are affected by CVE-2021-21805?

Affected: R-Seenet (Advantech) versions 2.4.12; Advantech versions >= Advantech R-SeeNet 2.4.12 (20.10.2020). The full list is in the CVE brief.

Is CVE-2021-21805 being exploited in the wild?

It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Oct 14, 2023.

Is CVE-2021-21805 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2021-21805?

No public exploit code is known.

Is there a fix for CVE-2021-21805?

No fixed version is listed yet; check the vendor advisory for mitigations.

How urgently should CVE-2021-21805 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

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Vulnerability Intelligence

CVE-2021-21805

CriticalExploited

An OS Command Injection vulnerability exists in the ping.php script functionality of Advantech R-SeeNet v 2.4.12 (20.10.2020).

Published Aug 5, 2021 · Updated Nov 21, 2024

Key Facts

Patch immediately

CVE-2021-21805 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting R-Seenet (Advantech), Advantech.
It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Oct 14, 2023. No public exploit code is known.
EPSS estimates a 70% probability of exploitation in the next 30 days.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

9.8

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

EPSS (30-day exploit likelihood)

70%

Higher than 99.3% of all scored CVEs

Exploited in the wild

Yes

2 catalog listings

Public exploit code

None known

Get the full CVE-2021-21805 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

An OS Command Injection vulnerability exists in the ping.php script functionality of Advantech R-SeeNet v 2.4.12 (20.10.2020). A specially crafted HTTP request can lead to arbitrary OS command execution. An attacker can send a crafted HTTP request to trigger this vulnerability.

Known-Exploited Catalog Listings

Catalog	Added	Remediation due	Ransomware use
Industry KEV feed	Dec 24, 2023	n/a	Not reported
CIRCL KEV	Oct 14, 2023	n/a	Not reported

Required action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Affected Products

2 affected entries in total

Product	Affected versions	Fixed in
R-SeenetAdvantech	2.4.12	n/a
Advantech	>= Advantech R-SeeNet 2.4.12 (20.10.2020)	n/a

Timeline

Publicly disclosed
Aug 5, 2021
Added to CIRCL KEV
Oct 14, 2023
Added to Industry KEV feed
Dec 24, 2023
Last updated
Nov 21, 2024

Weakness Type

CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

References

6 more references in the full CVE brief

FAQ

Common Questions.

An OS Command Injection vulnerability exists in the ping.php script functionality of Advantech R-SeeNet v 2.4.12 (20.10.2020).
Affected: R-Seenet (Advantech) versions 2.4.12; Advantech versions >= Advantech R-SeeNet 2.4.12 (20.10.2020). The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed, CIRCL KEV since Oct 14, 2023.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Is CVE-2021-21805 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.