CVE-2025-20134Network attack vector

Unauthenticated device reload via certificate double free

Published Aug 14, 2025 · Updated Aug 19, 2025

Double-free certificate processing in Cisco ASA Software 9.15 and earlier and FTD Software 6.7 and earlier allows remote attackers to reload devices. The certificate parser improperly parses an SSL/TLS certificate carried in crafted DNS traffic, freeing memory twice and forcing a reload. Exploitation requires a static NAT rule with DNS inspection enabled and packets matching that rule; service remains interrupted until the device reloads.

CVSS severity8.6
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free certificate processing in Cisco ASA Software 9.15 and earlier and FTD Software 6.7 and earlier allows remote attackers to reload devices. The certificate parser improperly parses an SSL/TLS certificate carried in crafted DNS traffic, freeing memory twice and forcing a reload. Exploitation requires a static NAT rule with DNS inspection enabled and packets matching that rule; service remains interrupted until the device reloads.

The record

CVE
CVE-2025-20134
Published
Aug 14, 2025
Updated
Aug 19, 2025
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-415, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 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=9.12.4.39
  2. Affected versionversion=9.12.4.40
  3. Affected versionversion=9.12.4.41
  4. Affected versionversion=9.12.4.47
  5. Affected versionversion=9.12.4.48
  6. Affected versionversion=9.12.4.50
  7. Affected versionversion=9.12.4.52
  8. Affected versionversion=9.12.4.54
  9. Affected versionversion=9.12.4.55
  10. Affected versionversion=9.12.4.56
  11. Affected versionversion=9.12.4.58
  12. Affected versionversion=9.12.4.62
  13. Affected versionversion=9.12.4.65
  14. Affected versionversion=9.12.4.67
  15. Affected versionversion=9.14.4.12
  16. Affected versionversion=9.14.4.13
  17. Affected versionversion=9.14.4.14
  18. Affected versionversion=9.14.4.15
  19. Affected versionversion=9.14.4.17
  20. Affected versionversion=9.14.4.22
  21. Affected versionversion=9.14.4.23
  22. Affected versionversion=9.14.4.24
  23. Affected versionversion=9.14.4.6
  24. Affected versionversion=9.14.4.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=9.12.4.39; version=9.12.4.40; version=9.12.4.41; version=9.12.4.47; version=9.12.4.48; version=9.12.4.50; version=9.12.4.52; version=9.12.4.54; version=9.12.4.55; version=9.12.4.56; version=9.12.4.58; version=9.12.4.62; version=9.12.4.65; version=9.12.4.67; version=9.14.4.12; version=9.14.4.13; version=9.14.4.14; version=9.14.4.15; version=9.14.4.17; version=9.14.4.22; version=9.14.4.23; version=9.14.4.24; version=9.14.4.6; version=9.14.4.7
ClamAV · Cisco Firepower Threat Defenseversion=6.4.0.15; version=6.4.0.16; version=6.4.0.17; version=6.4.0.18; version=6.6.5.2; version=6.6.7; version=6.6.7.1; version=6.6.7.2

Published CVSS scores

8.6Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

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.

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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-415Double Free
T1499.004Application or System Exploitation

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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