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Exploitation reportedNot in CISA KEV yet

CVE-2021-20617

Exploitation reported by one source. First attested on 2024-12-05 by GCVE · shadowserver.

  • Published2021-01-14

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

Improper access control vulnerability in acmailer ver. 4.0.1 and earlier, and acmailer DB ver. 1.1.3 and earlier allows remote attackers to execute an arbitrary OS command, or gain an administrative privilege which may result in obtaining the sensitive information on the server via unspecified vectors.

Timeline

dates in UTC
  1. 2021-01-1409:15CVE publishedNVD
  2. 2024-12-0509:00Listed as exploited by GCVEGCVE
  3. 2024-12-0509:00Exploitation first reportedGCVE

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-2021-20617?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20617?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Acmailer
BranchAffectedFixed in
4.0≤ 4.0.1no fix published
Acmailer acmailer db
BranchAffectedFixed in
1.1≤ 1.1.3no fix published

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

Fix

Advisories and patches

Detection

read 2026-11-02 22:42 UTC
Nuclei template
available
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

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
2021-01-14
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-20617?

Improper access control vulnerability in acmailer ver. 4.0.1 and earlier, and acmailer DB ver. 1.1.3 and earlier allows remote attackers to execute an arbitrary OS command, or gain an administrative privilege which may result in obtaining the sensitive information on the server via unspecified vectors.

Is CVE-2021-20617 actively exploited?

Active exploitation of CVE-2021-20617 has not been confirmed. Its EPSS score was 7.4% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-20617?

CVE-2021-20617 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.

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Sources for this record