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Vulnerabilities

Vulnerability · CVE-2021-27877

Veritas Backup Exec Agent Improper Authentication Vulnerability

Published Mar 1, 2021 · catalog updated Jun 16, 2026 · Veritas Backup Exec Agent

Patch now

CVE-2021-27877 is in the CISA known-exploited catalog, due Apr 28, 2023. Confirm Veritas Backup Exec Agent against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
64.91%
Remediation
Remediation guidance
Affected products
cpe veritas/backup exec · vendor Veritas Backup Exec Agent

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe veritas/backup execversion unspecified
  • vendor Veritas Backup Exec Agentversion unspecified

How to fix CVE-2021-27877

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-27877 is in the CISA known-exploited catalog, due Apr 28, 2023. Confirm Veritas Backup Exec Agent against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply updates per vendor instructions.

What should an analyst verify?

CWE-287: Improper Authentication. EPSS 64.91%. The CISA KEV listing is the exploitation evidence. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 1, 2021 · Catalog

    Detected

    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.

  2. Apr 7, 2023 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Apr 28, 2023 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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

  • CISA KEVConfirmed exploitationCVE-2021-27877

    Veritas Backup Exec (BE) Agent contains an improper authentication vulnerability that could allow an attacker unauthorized access to the BE Agent via SHA authentication scheme.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-27877

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-27877

    30-day exploitation probability 64.9%

    first.org
  • Metasploit ModulesPublic exploit moduleexploit_multi/veritas/beagent_sha_auth_rce

    Public module reference (excellent). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDVulnerability recordCVE-2021-27877

    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 e

    nvd.nist.gov
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • VulnCheck KEVConfirmed exploitationCVE-2021-27877

    Veritas Backup Exec (BE) Agent contains an improper authentication vulnerability that could allow an attacker unauthorized access to the BE Agent via SHA authentication scheme.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.