Veritas Backup Exec Agent Improper Authentication Vulnerability
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.
- Vendor
- Veritas
- Product
- Backup Exec Agent
- CVSS
- 8.2
- EPSS (exploit probability)
- 64.9%
- Status
- kevransomware use
- CISA patch-by (BOD 22-01)
- Added to KEV
Is CVE-2021-27877 being exploited?
Yes. CISA added CVE-2021-27877 to its Known Exploited Vulnerabilities catalog on . CISA only lists a CVE when it has reliable evidence of exploitation in the wild. CISA marks it as known to be used in ransomware campaigns.
FIRST's EPSS model puts the probability of exploitation activity in the next 30 days at 64.9% (scored October 14, 2026).
- CISA KEV[ LISTED ]
- ENISA EUVD (exploited)[ — ]
- CIRCL KEV[ — ]
Catalog snapshot 2026-10-21. Full cross-catalog view: /kev-comparison
What to do
CISA required actionApply updates per vendor instructions.
US federal civilian agencies must remediate by (21 days after listing) under BOD 22-01. Everyone else: that deadline is a sensible upper bound, not a target. Vendor guidance and the NVD record are linked under Source above.
Other Veritas Backup Exec Agent CVEs we track
| CVE / Vulnerability | Severity | CVSS | EPSS | Added to KEV |
|---|---|---|---|---|
| CVE-2021-27878 Veritas Backup Exec Agent Command Execution Vulnerabilityransomware use | [ HIGH ] | 8.8 | 24.0% | |
| CVE-2021-27876 Veritas Backup Exec Agent File Access Vulnerabilityransomware use | [ HIGH ] | 8.1 | 13.5% |