Skip to main content
ExploitedIn CISA KEVFix available

CVE-2021-27877

Exploitation confirmed. First attested on 2023-04-07 by CISA-ADP, CISA KEV, GCVE · kevintel.

  • Published2021-03-01
  • Fixed in21.2

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2021-03-0122:15CVE publishedNVD
  2. 2023-04-07Added to the CISA KEV catalogCISA KEV
  3. 2023-04-07Listed as exploited by GCVEGCVE
  4. 2023-04-07Exploitation first reportedCISA KEV
  5. 2023-12-2205:01SSVC exploitation set to activeCISA-ADP

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-27877?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-27877?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Veritas backup exec
BranchAffectedFixed in
21.2< 21.221.2

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Veritas backup exec to 21.2
  2. CISA’s required action: Apply updates per vendor instructions.due 2023-04-28

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
available
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedyashswarup12/CVE-2021-27877-PoC
PoC-in-GitHub
Metasploit modules
1 moduleexploit/multi/veritas/beagent_sha_auth_rcerank: excellentModule metadata: Metasploit Framework, © Rapid7, Inc., BSD-3-Clause.
Metasploit Framework

CISA Known Exploited Vulnerability

Date Added
2023-04-07
Patch Due Date
2023-04-28
Ransomware Use
Known
Required Action
Apply updates per vendor instructions.

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-03-01
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-grhg-3w4v-cp2r

Frequently asked questions

What is CVE-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 exploit this scheme to gain unauthorized access to an Agent and execute privileged commands.

Is CVE-2021-27877 actively exploited?

Yes. CVE-2021-27877 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2023-04-28.

What is the CVSS score for CVE-2021-27877?

CVE-2021-27877 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Hear about the next vulnerability in your software

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, April 2023Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database

Sources for this record