CVE-2021-26471: Unauthenticated remote command execution in Vembu products

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-06-08 · updated 2026-06-17

Description

In VembuBDR before 4.2.0.1 and VembuOffsiteDR before 4.2.0.1, the http API located at /sgwebservice_o.php accepts a command argument. Using this command argument an unauthenticated attacker can execute arbitrary shell commands.

Affected products

Vembu Bdr Suite: before 4.2.0.1 — fixed in 4.2.0.1
Vembu Offsite Dr: before 4.2.0.1 — fixed in 4.2.0.1

How to fix

Upgrade to a fixed version: Vembu Bdr Suite 4.2.0.1; Vembu Offsite Dr 4.2.0.1. Check the vendor advisory for mitigations.

References

https://csirt.divd.nl/2021/05/11/Vembu-zero-days/
https://csirt.divd.nl/cases/DIVD-2020-00011/
https://csirt.divd.nl/cves/CVE-2021-26471/
https://www.wbsec.nl/vembu
https://csirt.divd.nl/2021/05/11/Vembu-zero-days/
https://csirt.divd.nl/cases/DIVD-2020-00011/
https://csirt.divd.nl/cves/CVE-2021-26471/
https://www.wbsec.nl/vembu

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