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PatchSiren cyber security CVE debrief

CVE-2021-27877 Veritas CVE debrief

CVE-2021-27877 is a Veritas Backup Exec Agent improper authentication issue that CISA added to the Known Exploited Vulnerabilities (KEV) catalog on 2023-04-07. CISA also marks the vulnerability as having known ransomware campaign use. For defenders, the key takeaway is urgency: systems running the affected Backup Exec Agent should be prioritized for vendor-directed updates and validation.

Vendor
Veritas
Product
Backup Exec Agent
CVSS
HIGH 8.2
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

Backup and infrastructure administrators, endpoint/server teams running Veritas Backup Exec Agent, vulnerability management teams, and incident responders protecting backup environments.

Technical summary

The source corpus identifies the issue as an improper authentication vulnerability in Veritas Backup Exec Agent. The CISA KEV entry records the CVE as actively exploited and notes known ransomware campaign use. The supplied materials do not include additional technical details, so remediation guidance should follow the linked Veritas advisory and vendor update instructions.

Defensive priority

High. KEV inclusion plus known ransomware campaign use indicates elevated risk and a need to prioritize patching and exposure review.

Recommended defensive actions

  • Apply updates per Veritas vendor instructions for the affected Backup Exec Agent product.
  • Inventory environments for Veritas Backup Exec Agent instances and confirm which are affected.
  • Prioritize exposed, internet-reachable, or backup-critical systems for remediation first.
  • Validate that remediation completed successfully and that affected hosts are no longer running vulnerable versions.
  • Review backup infrastructure monitoring and incident response readiness because CISA notes known ransomware campaign use.

Evidence notes

This debrief is based on the supplied CISA KEV metadata and official links. The corpus confirms the CVE, product, KEV dateAdded/dateDue, and knownRansomwareCampaignUse. It does not include the full text of the Veritas advisory or NVD record, so no additional vulnerability mechanics or version-specific claims are made here.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-27877 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-27877

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-27877 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-27877

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.