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PatchSiren cyber security CVE debrief

CVE-2021-27876 Veritas CVE debrief

CVE-2021-27876 is a Veritas Backup Exec Agent file access vulnerability that CISA added to its Known Exploited Vulnerabilities catalog on 2023-04-07. CISA’s entry also marks known ransomware campaign use, which makes this a defensive priority for any environment running the affected agent. The supplied corpus does not include CVSS scoring or detailed impact analysis, so the safest interpretation is to treat it as an actively exploited backup-infrastructure risk and follow vendor remediation guidance promptly.

Vendor
Veritas
Product
Backup Exec Agent
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2023-04-07
Original CVE updated
2023-04-07
Advisory published
2023-04-07
Advisory updated
2023-04-07

Who should care

Organizations that use Veritas Backup Exec Agent, especially backup administrators, infrastructure operations, and incident response teams. Because CISA lists it in KEV with known ransomware campaign use, defenders responsible for backup systems and adjacent management networks should prioritize it.

Technical summary

The available source corpus describes CVE-2021-27876 only as a Veritas Backup Exec Agent file access vulnerability. It does not provide exploit mechanics, affected versions, privilege impact, or attack preconditions. The authoritative signal in the corpus is CISA KEV inclusion, which indicates known exploitation, along with a note that ransomware campaign use is known. For technical follow-up, use the official vendor advisory and the NVD/CVE record to confirm affected versions and remediation steps.

Defensive priority

High. CISA placed the issue in KEV and marked known ransomware campaign use, so remediation should be prioritized wherever Veritas Backup Exec Agent is deployed.

Recommended defensive actions

  • Apply updates per Veritas vendor instructions.
  • Identify all systems running Veritas Backup Exec Agent and confirm whether they are affected.
  • Prioritize patching or compensating controls for internet-facing or backup-critical systems first.
  • Review backup environment access paths and administrative exposure around the agent.
  • Use the official vendor advisory and NVD/CVE record to confirm affected versions and remediation details.
  • Verify remediation completed before the CISA KEV due date if still pending in your environment.

Evidence notes

Source evidence is limited to the CISA KEV feed entry and official reference links. The corpus confirms: vendor Veritas, product Backup Exec Agent, vulnerability name "Veritas Backup Exec Agent File Access Vulnerability," date added 2023-04-07, due date 2023-04-28, and known ransomware campaign use marked "Known." The corpus does not supply CVSS, affected versions, exploit method, or a full impact statement, so this debrief avoids unstated technical claims.

Official resources

Publicly listed by CISA in the Known Exploited Vulnerabilities catalog on 2023-04-07 with known ransomware campaign use. This debrief is defensive only and intentionally excludes exploit details.