CVE-2025-20219Network attack vector

Unauthenticated loopback access-control bypass

Published Aug 14, 2025 · Updated Aug 14, 2025

Access-control bypass in Cisco Secure Firewall ASA and FTD Software allows remote attackers to reach enabled loopback interfaces. The implementation improperly enforces configured access-control rules when traffic is addressed to a loopback interface, forwarding packets that the rules should block. Exploitation is unauthenticated and network-reachable, but it requires a configured and enabled loopback interface, which Cisco states is not the default; the bounded consequence is unauthorized traffic delivery to services on that interface.

CVSS severity5.3
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Access-control bypass in Cisco Secure Firewall ASA and FTD Software allows remote attackers to reach enabled loopback interfaces. The implementation improperly enforces configured access-control rules when traffic is addressed to a loopback interface, forwarding packets that the rules should block. Exploitation is unauthenticated and network-reachable, but it requires a configured and enabled loopback interface, which Cisco states is not the default; the bounded consequence is unauthorized traffic delivery to services on that interface.

The record

CVE
CVE-2025-20219
Published
Aug 14, 2025
Updated
Aug 14, 2025
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-284, T1211
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 14, 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=9.18.2
  2. Affected versionversion=9.18.2.5
  3. Affected versionversion=9.18.2.7
  4. Affected versionversion=9.18.2.8
  5. Affected versionversion=9.18.3
  6. Affected versionversion=9.18.3.39
  7. Affected versionversion=9.18.3.46
  8. Affected versionversion=9.18.3.53
  9. Affected versionversion=9.18.3.55
  10. Affected versionversion=9.18.3.56
  11. Affected versionversion=9.18.4
  12. Affected versionversion=9.18.4.22
  13. Affected versionversion=9.18.4.24
  14. Affected versionversion=9.18.4.29
  15. Affected versionversion=9.18.4.34
  16. Affected versionversion=9.18.4.40
  17. Affected versionversion=9.18.4.47
  18. Affected versionversion=9.18.4.5
  19. Affected versionversion=9.18.4.50
  20. Affected versionversion=9.18.4.8
  21. Affected versionversion=9.19.1
  22. Affected versionversion=9.19.1.12
  23. Affected versionversion=9.19.1.18
  24. Affected versionversion=9.19.1.22
  25. Affected versionversion=9.19.1.24
  26. Affected versionversion=9.19.1.27
  27. Affected versionversion=9.19.1.28
  28. Affected versionversion=9.19.1.31
  29. Affected versionversion=9.19.1.37
  30. Affected versionversion=9.19.1.38
  31. Affected versionversion=9.19.1.5
  32. Affected versionversion=9.19.1.9
  33. Affected versionversion=9.20.1
  34. Affected versionversion=9.20.1.5
  35. Affected versionversion=9.20.2
  36. Affected versionversion=9.20.2.10
  37. Affected versionversion=9.20.2.21
  38. Affected versionversion=9.20.2.22
  39. Affected versionversion=9.20.3
  40. Affected versionversion=9.20.3.4
  41. Affected versionversion=9.20.3.7
  42. Affected versionversion=9.20.3.9
  43. Affected versionversion=9.22.1.1
  44. Affected versionversion=9.22.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=9.18.2; version=9.18.2.5; version=9.18.2.7; version=9.18.2.8; version=9.18.3; version=9.18.3.39; version=9.18.3.46; version=9.18.3.53; version=9.18.3.55; version=9.18.3.56; version=9.18.4; version=9.18.4.22; version=9.18.4.24; version=9.18.4.29; version=9.18.4.34; version=9.18.4.40; version=9.18.4.47; version=9.18.4.5; version=9.18.4.50; version=9.18.4.8; version=9.19.1; version=9.19.1.12; version=9.19.1.18; version=9.19.1.22; version=9.19.1.24; version=9.19.1.27; version=9.19.1.28; version=9.19.1.31; version=9.19.1.37; version=9.19.1.38; version=9.19.1.5; version=9.19.1.9; version=9.20.1; version=9.20.1.5; version=9.20.2; version=9.20.2.10; version=9.20.2.21; version=9.20.2.22; version=9.20.3; version=9.20.3.4; version=9.20.3.7; version=9.20.3.9; version=9.22.1.1; version=9.22.1.2
ClamAV · Cisco Firepower Threat Defenseversion=7.3.0; version=7.3.1; version=7.3.1.1; version=7.3.1.2; version=7.4.0; version=7.4.1; version=7.4.1.1; version=7.4.2; version=7.4.2.1; version=7.6.0

Published CVSS scores

5.3Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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
T1211Exploitation for Defense Evasion

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo