CVE-2025-20153Network attack vector

Unauthenticated email-filter bypass via crafted messages

Published Feb 19, 2025 · Updated Feb 19, 2025

Improper access control in Cisco Secure Email Gateway through 16.0.0-050 allows remote attackers to bypass email filters via crafted email. The email filtering mechanism improperly handles a crafted message as it passes through the gateway, causing configured deny rules not to be enforced. No authentication or user interaction is required; successful exploitation permits email that policy should deny to flow through the device.

CVSS severity5.8
Medium
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Cisco Secure Email Gateway through 16.0.0-050 allows remote attackers to bypass email filters via crafted email. The email filtering mechanism improperly handles a crafted message as it passes through the gateway, causing configured deny rules not to be enforced. No authentication or user interaction is required; successful exploitation permits email that policy should deny to flow through the device.

The record

CVE
CVE-2025-20153
Published
Feb 19, 2025
Updated
Feb 19, 2025
Vendor
ClamAV
Product
Cisco Secure Email
Classifications
CWE-284, T1566
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 19, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=13.0.0-392
  2. Affected versionversion=13.0.5-007
  3. Affected versionversion=13.5.1-277
  4. Affected versionversion=13.5.4-038
  5. Affected versionversion=14.0.0-698
  6. Affected versionversion=14.2.0-620
  7. Affected versionversion=14.2.1-020
  8. Affected versionversion=14.3.0-032
  9. Affected versionversion=15.0.0-104
  10. Affected versionversion=15.0.1-030
  11. Affected versionversion=15.0.3-002
  12. Affected versionversion=15.5.0-048
  13. Affected versionversion=15.5.1-055
  14. Affected versionversion=15.5.2-018
  15. Affected versionversion=16.0.0-050

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Secure Emailversion=13.0.0-392; version=13.0.5-007; version=13.5.1-277; version=13.5.4-038; version=14.0.0-698; version=14.2.0-620; version=14.2.1-020; version=14.3.0-032; version=15.0.0-104; version=15.0.1-030; version=15.0.3-002; version=15.5.0-048; version=15.5.1-055; version=15.5.2-018; version=16.0.0-050

Published CVSS scores

5.8CiscoCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1566Phishing

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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