Is CVE-2021-27899 actively exploited?

No active exploitation of CVE-2021-27899 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-27899 be exploited remotely?

Yes. CVE-2021-27899 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-27899?

CVE-2021-27899 has a CVSS score of 7.4 (HIGH).

HOME VULNERABILITIESCVE-2021-27899

HIGH

CVE-2021-27899

CWE-295Published: April 6, 2021· Updated: Jun 17, 2026

7.4

CVSS v3.1

Official Description

The Proofpoint Insider Threat Management Agents (formerly ObserveIT Agent) for MacOS and Linux perform improper validation of the ITM Server's certificate, which enables a remote attacker to intercept and alter these communications using a man-in-the-middle attack. All versions before 7.11.1 are affected. Agents for Windows and Cloud are not affected.

NVD Source

Technical Analysis

CVE-2021-27899 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.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 7.4.