critical Known exploitedREV. 01
CVE-2021-27877Veritas Backup Exec — an obsolete login still accepted
Backup Exec kept accepting a legacy authentication scheme that current versions no longer use, so an attacker who reaches an agent over the network logs in with it and runs privileged commands. Fixed in 21.2.
Read the risk
THE VITAL STATS- CVSS score
- 9.8/ 10 CVSS v3.1
- EPSS probability
- 65% Likelihood of exploitation
- Attack complexity
- Low Conditions needed to exploit
- Known exploited
- Yes — CISA KEV
- CVE published
- 2021-03-01
- Added to KEV
- 2023-04-07
- Exploit published
- Yes
- Confidence
- medium
- Kill chain
- initial access
- MITRE ATT&CK
- T1190
- Severity
- critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attacker needsNetwork access to a Backup Exec agent.
Fixed inVeritas Backup Exec >= 21.2
Behind the card
4 REFERENCES- 01CVE recordNVD recordnvd.nist.gov
- 02CISACISA Known Exploited Vulnerabilities catalogcisa.gov
- 03Vendor advisoryveritas.comveritas.com
- 04Exploitpacketstormsecurity.compacketstormsecurity.com
Field-level provenanceTRACE THE SOURCES +
Which source supports each field, when it was retrieved, and who extracted it.
| Fields | Source | Retrieved | Extractor | Confidence |
|---|---|---|---|---|
| cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_at | nvd.nist.gov | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| exploitation.known_exploited, exploitation.kev_added | cisa.gov | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| epss | api.first.org | 2026-09-24 | scrty-crds-pipeline/0.1 | high |
| title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisites | nvd.nist.gov | 2026-09-24 | claude-code | high |
Printing history
THE RECORD- r1Initial base card
First printing. This card has not been reprinted since publication.