CVE-2026-20049Network attack vector

Authenticated device reload via undersized GCM buffer

Published Mar 4, 2026 · Updated Mar 4, 2026

Denial of service in Cisco Secure Firewall ASA and FTD Software allows remote authenticated users to reload devices with crafted GCM IKEv2 traffic. IPsec IKEv2 traffic processing allocates a memory block too small for attacker-crafted GCM-encrypted input. Exploitation requires a vulnerable release, at least one GCM IKEv2 proposal, and valid VPN credentials; success causes an unexpected device reload.

CVSS severity7.7
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco Secure Firewall ASA and FTD Software allows remote authenticated users to reload devices with crafted GCM IKEv2 traffic. IPsec IKEv2 traffic processing allocates a memory block too small for attacker-crafted GCM-encrypted input. Exploitation requires a vulnerable release, at least one GCM IKEv2 proposal, and valid VPN credentials; success causes an unexpected device reload.

The record

CVE
CVE-2026-20049
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-131, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 2026Record 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=9.12.4.10
  2. Affected versionversion=9.12.4.13
  3. Affected versionversion=9.12.4.18
  4. Affected versionversion=9.12.4.24
  5. Affected versionversion=9.12.4.26
  6. Affected versionversion=9.12.4.29
  7. Affected versionversion=9.12.4.30
  8. Affected versionversion=9.12.4.35
  9. Affected versionversion=9.12.4.37
  10. Affected versionversion=9.12.4.38
  11. Affected versionversion=9.12.4.39
  12. Affected versionversion=9.12.4.40
  13. Affected versionversion=9.12.4.41
  14. Affected versionversion=9.12.4.47
  15. Affected versionversion=9.12.4.48
  16. Affected versionversion=9.12.4.50
  17. Affected versionversion=9.12.4.52
  18. Affected versionversion=9.12.4.54
  19. Affected versionversion=9.12.4.55
  20. Affected versionversion=9.12.4.56
  21. Affected versionversion=9.12.4.58
  22. Affected versionversion=9.12.4.62
  23. Affected versionversion=9.12.4.65
  24. Affected versionversion=9.12.4.67
  25. Affected versionversion=9.12.4.7
  26. Affected versionversion=9.12.4.8
  27. Affected versionversion=9.16.1
  28. Affected versionversion=9.16.1.28
  29. Affected versionversion=9.16.2
  30. Affected versionversion=9.16.2.11
  31. Affected versionversion=9.16.2.13
  32. Affected versionversion=9.16.2.14
  33. Affected versionversion=9.16.2.3
  34. Affected versionversion=9.16.2.7
  35. Affected versionversion=9.16.3
  36. Affected versionversion=9.16.3.14
  37. Affected versionversion=9.16.3.15
  38. Affected versionversion=9.16.3.19
  39. Affected versionversion=9.16.3.23
  40. Affected versionversion=9.16.3.3
  41. Affected versionversion=9.16.4
  42. Affected versionversion=9.16.4.14
  43. Affected versionversion=9.16.4.19
  44. Affected versionversion=9.16.4.27
  45. Affected versionversion=9.16.4.38
  46. Affected versionversion=9.16.4.39
  47. Affected versionversion=9.16.4.42
  48. Affected versionversion=9.16.4.48
  49. Affected versionversion=9.16.4.55
  50. Affected versionversion=9.16.4.57
  51. Affected versionversion=9.16.4.61
  52. Affected versionversion=9.16.4.62
  53. Affected versionversion=9.16.4.67
  54. Affected versionversion=9.16.4.70
  55. Affected versionversion=9.16.4.71
  56. Affected versionversion=9.16.4.76
  57. Affected versionversion=9.16.4.82
  58. Affected versionversion=9.16.4.84
  59. Affected versionversion=9.16.4.9
  60. Affected versionversion=9.17.1
  61. Affected versionversion=9.17.1.10
  62. Affected versionversion=9.17.1.11
  63. Affected versionversion=9.17.1.13
  64. Affected versionversion=9.17.1.15
  65. Affected versionversion=9.17.1.20
  66. Affected versionversion=9.17.1.30
  67. Affected versionversion=9.17.1.33
  68. Affected versionversion=9.17.1.39
  69. Affected versionversion=9.17.1.45
  70. Affected versionversion=9.17.1.46
  71. Affected versionversion=9.17.1.7
  72. Affected versionversion=9.17.1.9
  73. Affected versionversion=9.18.1
  74. Affected versionversion=9.18.1.3
  75. Affected versionversion=9.18.2
  76. Affected versionversion=9.18.2.5
  77. Affected versionversion=9.18.2.7
  78. Affected versionversion=9.18.2.8
  79. Affected versionversion=9.18.3
  80. Affected versionversion=9.18.3.39
  81. Affected versionversion=9.18.3.46
  82. Affected versionversion=9.18.3.53
  83. Affected versionversion=9.18.3.55
  84. Affected versionversion=9.18.3.56
  85. Affected versionversion=9.18.4
  86. Affected versionversion=9.18.4.22
  87. Affected versionversion=9.18.4.24
  88. Affected versionversion=9.18.4.29
  89. Affected versionversion=9.18.4.34
  90. Affected versionversion=9.18.4.40
  91. Affected versionversion=9.18.4.47
  92. Affected versionversion=9.18.4.5
  93. Affected versionversion=9.18.4.50
  94. Affected versionversion=9.18.4.52
  95. Affected versionversion=9.18.4.53
  96. Affected versionversion=9.18.4.57
  97. Affected versionversion=9.18.4.8
  98. Affected versionversion=9.19.1
  99. Affected versionversion=9.19.1.12
  100. Affected versionversion=9.19.1.18
  101. Affected versionversion=9.19.1.22
  102. Affected versionversion=9.19.1.24
  103. Affected versionversion=9.19.1.27
  104. Affected versionversion=9.19.1.28
  105. Affected versionversion=9.19.1.31
  106. Affected versionversion=9.19.1.37
  107. Affected versionversion=9.19.1.38
  108. Affected versionversion=9.19.1.42
  109. Affected versionversion=9.19.1.5
  110. Affected versionversion=9.19.1.9
  111. Affected versionversion=9.20.1
  112. Affected versionversion=9.20.1.5
  113. Affected versionversion=9.20.2
  114. Affected versionversion=9.20.2.10
  115. Affected versionversion=9.20.2.21
  116. Affected versionversion=9.20.2.22
  117. Affected versionversion=9.20.3
  118. Affected versionversion=9.20.3.10
  119. Affected versionversion=9.20.3.13
  120. Affected versionversion=9.20.3.16
  121. Affected versionversion=9.20.3.20
  122. Affected versionversion=9.20.3.4
  123. Affected versionversion=9.20.3.7
  124. Affected versionversion=9.20.3.9
  125. Affected versionversion=9.22.1.1
  126. Affected versionversion=9.22.1.2
  127. Affected versionversion=9.22.1.3
  128. Affected versionversion=9.22.1.6
  129. Affected versionversion=9.22.2
  130. Affected versionversion=9.23.1
  131. Affected versionversion=9.23.1.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=9.12.4.10; version=9.12.4.13; version=9.12.4.18; version=9.12.4.24; version=9.12.4.26; version=9.12.4.29; version=9.12.4.30; version=9.12.4.35; version=9.12.4.37; version=9.12.4.38; version=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=9.12.4.7; version=9.12.4.8; version=9.16.1; version=9.16.1.28; version=9.16.2; version=9.16.2.11; version=9.16.2.13; version=9.16.2.14; version=9.16.2.3; version=9.16.2.7; version=9.16.3; version=9.16.3.14; version=9.16.3.15; version=9.16.3.19; version=9.16.3.23; version=9.16.3.3; version=9.16.4; version=9.16.4.14; version=9.16.4.19; version=9.16.4.27; version=9.16.4.38; version=9.16.4.39; version=9.16.4.42; version=9.16.4.48; version=9.16.4.55; version=9.16.4.57; version=9.16.4.61; version=9.16.4.62; version=9.16.4.67; version=9.16.4.70; version=9.16.4.71; version=9.16.4.76; version=9.16.4.82; version=9.16.4.84; version=9.16.4.9; version=9.17.1; version=9.17.1.10; version=9.17.1.11; version=9.17.1.13; version=9.17.1.15; version=9.17.1.20; version=9.17.1.30; version=9.17.1.33; version=9.17.1.39; version=9.17.1.45; version=9.17.1.46; version=9.17.1.7; version=9.17.1.9; version=9.18.1; version=9.18.1.3; version=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=9.18.4.52; version=9.18.4.53; version=9.18.4.57; 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=9.19.1.42; 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=9.20.3.10; version=9.20.3.13; version=9.20.3.16; version=9.20.3.20; 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; version=9.22.1.3; version=9.22.1.6; version=9.22.2; version=9.23.1; version=9.23.1.3
ClamAV · Cisco Secure Firewall Threat Defenseversion=6.4.0.10; version=6.4.0.11; version=6.4.0.12; version=6.4.0.13; version=6.4.0.14; version=6.4.0.15; version=6.4.0.16; version=6.4.0.17; version=6.4.0.18; version=7.0.0; version=7.0.0.1; version=7.0.1; version=7.0.1.1; version=7.0.2; version=7.0.2.1; version=7.0.3; version=7.0.4; version=7.0.5; version=7.0.6; version=7.0.6.1; version=7.0.6.2; version=7.0.6.3; version=7.0.7; version=7.0.8; version=7.0.8.1; version=7.1.0; version=7.1.0.1; version=7.1.0.2; version=7.1.0.3; version=7.2.0; version=7.2.0.1; version=7.2.1; version=7.2.10; version=7.2.10.2; version=7.2.2; version=7.2.3; version=7.2.4; version=7.2.4.1; version=7.2.5; version=7.2.5.1; version=7.2.5.2; version=7.2.6; version=7.2.7; version=7.2.8; version=7.2.8.1; version=7.2.9; version=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=7.4.2.2; version=7.4.2.3; version=7.4.2.4; version=7.6.0; version=7.6.1; version=7.6.2; version=7.6.2.1; version=7.7.0; version=7.7.10; version=7.7.10.1

Published CVSS scores

7.7CiscoCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-131Incorrect Calculation of Buffer Size
T1499Endpoint Denial of Service

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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