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CVE-2021-27877

High CVSS 8.2 Known exploited

Published 2021-03-01 · last changed 2026-06-17 · added to CISA KEV 2023-04-07

This one is being exploited in the wild.

CISA added CVE-2021-27877 to the Known Exploited Vulnerabilities catalog on 2023-04-07. Federal agencies are required to remediate it on a deadline. If you have affected machines, this is the class of finding that moves ahead of the rest of the queue.

The fix

We hold no Microsoft remediation data for CVE-2021-27877, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

An issue was discovered in Veritas Backup Exec before 21.2. It supports multiple authentication schemes: SHA authentication is one of these. This authentication scheme is no longer used in current versions of the product, but hadn't yet been disabled. An attacker could remotely exploit this scheme to gain unauthorized access to an Agent and execute privileged commands.

Sources

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