November 13, 2026 Follow Egret
CVE-2021-27877 · CVE record: PUBLISHED

Veritas Backup Exec Agent Improper Authentication Vulnerability

n/a n/a

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.

Exploitation evidence

Known exploited · CISA KEV listed

Added 2023-04-07. Ransomware campaign use: Known.

CISA required action: Apply updates per vendor instructions.

CISA due date: 2023-04-28. This is the catalog’s deadline, not an assessment of your organization’s exposure.

KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗

Reported products and versions

n/a / n/a

Default status: Not specified

  • affected: n/a

Fixes and workarounds

No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.

Sources and related reporting

CVE Program record ↗ · Download tracked evidence as JSON

Observed change timeline

History begins when Egret first downloads each source. It is not the complete upstream CVE history.

12 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-12",
  "epss": 0.6491,
  "percentile": 0.99259
}
10 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-10",
  "epss": 0.6491,
  "percentile": 0.99254
}
09 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-09",
  "epss": 0.6491,
  "percentile": 0.99253
}
08 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-08",
  "epss": 0.6491,
  "percentile": 0.99253
}
07 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-07",
  "epss": 0.6491,
  "percentile": 0.99253
}
06 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-06",
  "epss": 0.6491,
  "percentile": 0.99252
}
06 Nov 2026, 06:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-05",
  "epss": 0.6491,
  "percentile": 0.99251
}
05 Nov 2026, 18:20 Jerusalem · CVE Program record changed

Stored CNA snapshot at this observation.

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04 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-04",
  "epss": 0.6491,
  "percentile": 0.9925
}
03 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-03",
  "epss": 0.6491,
  "percentile": 0.99249
}
03 Nov 2026, 02:22 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-02",
  "epss": 0.6491,
  "percentile": 0.99248
}
03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed

Stored KEV snapshot at this observation.

{
  "cveID": "CVE-2021-27877",
  "cwes": [
    "CWE-287"
  ],
  "dateAdded": "2023-04-07",
  "dueDate": "2023-04-28",
  "forensicTriage": "No",
  "knownRansomwareCampaignUse": "Known",
  "notes": "https://www.veritas.com/support/en_US/security/VTS21-001; https://nvd.nist.gov/vuln/detail/CVE-2021-27877",
  "product": "Backup Exec Agent",
  "requiredAction": "Apply updates per vendor instructions.",
  "shortDescription": "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.",
  "vendorProject": "Veritas",
  "vulnerabilityName": "Veritas Backup Exec Agent Improper Authentication Vulnerability"
}
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