CVE-2025-20133Network attack vector

Unauthenticated VPN authentication interruption via crafted request

Published Aug 14, 2025 · Updated Aug 14, 2025

Denial of service in Cisco ASA and FTD Remote Access SSL VPN web servers allows remote attackers to halt authentication requests. The authentication handler ineffectively validates user-controlled request data before processing it, allowing the request to leave the VPN service unresponsive. The device must expose an SSL listen socket for the affected feature; exploitation interrupts new VPN authentication without reported data disclosure or modification.

CVSS severity8.6
High
EPSS probability0.74%
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 ASA and FTD Remote Access SSL VPN web servers allows remote attackers to halt authentication requests. The authentication handler ineffectively validates user-controlled request data before processing it, allowing the request to leave the VPN service unresponsive. The device must expose an SSL listen socket for the affected feature; exploitation interrupts new VPN authentication without reported data disclosure or modification.

The record

CVE
CVE-2025-20133
Published
Aug 14, 2025
Updated
Aug 14, 2025
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-835, T1499
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=9.12.1
  2. Affected versionversion=9.12.1.2
  3. Affected versionversion=9.12.1.3
  4. Affected versionversion=9.12.2
  5. Affected versionversion=9.12.2.1
  6. Affected versionversion=9.12.2.4
  7. Affected versionversion=9.12.2.5
  8. Affected versionversion=9.12.2.9
  9. Affected versionversion=9.12.3
  10. Affected versionversion=9.12.3.12
  11. Affected versionversion=9.12.3.2
  12. Affected versionversion=9.12.3.7
  13. Affected versionversion=9.12.3.9
  14. Affected versionversion=9.12.4
  15. Affected versionversion=9.12.4.10
  16. Affected versionversion=9.12.4.13
  17. Affected versionversion=9.12.4.18
  18. Affected versionversion=9.12.4.2
  19. Affected versionversion=9.12.4.24
  20. Affected versionversion=9.12.4.26
  21. Affected versionversion=9.12.4.29
  22. Affected versionversion=9.12.4.30
  23. Affected versionversion=9.12.4.35
  24. Affected versionversion=9.12.4.37
  25. Affected versionversion=9.12.4.38
  26. Affected versionversion=9.12.4.39
  27. Affected versionversion=9.12.4.4
  28. Affected versionversion=9.12.4.40
  29. Affected versionversion=9.12.4.41
  30. Affected versionversion=9.12.4.47
  31. Affected versionversion=9.12.4.48
  32. Affected versionversion=9.12.4.50
  33. Affected versionversion=9.12.4.52
  34. Affected versionversion=9.12.4.54
  35. Affected versionversion=9.12.4.55
  36. Affected versionversion=9.12.4.56
  37. Affected versionversion=9.12.4.58
  38. Affected versionversion=9.12.4.62
  39. Affected versionversion=9.12.4.65
  40. Affected versionversion=9.12.4.67
  41. Affected versionversion=9.12.4.7
  42. Affected versionversion=9.12.4.8
  43. Affected versionversion=9.14.1
  44. Affected versionversion=9.14.1.10
  45. Affected versionversion=9.14.1.15
  46. Affected versionversion=9.14.1.19
  47. Affected versionversion=9.14.1.30
  48. Affected versionversion=9.14.1.6
  49. Affected versionversion=9.14.2
  50. Affected versionversion=9.14.2.13
  51. Affected versionversion=9.14.2.15
  52. Affected versionversion=9.14.2.4
  53. Affected versionversion=9.14.2.8
  54. Affected versionversion=9.14.3
  55. Affected versionversion=9.14.3.1
  56. Affected versionversion=9.14.3.11
  57. Affected versionversion=9.14.3.13
  58. Affected versionversion=9.14.3.15
  59. Affected versionversion=9.14.3.18
  60. Affected versionversion=9.14.3.9
  61. Affected versionversion=9.14.4
  62. Affected versionversion=9.14.4.12
  63. Affected versionversion=9.14.4.13
  64. Affected versionversion=9.14.4.14
  65. Affected versionversion=9.14.4.15
  66. Affected versionversion=9.14.4.17
  67. Affected versionversion=9.14.4.22
  68. Affected versionversion=9.14.4.23
  69. Affected versionversion=9.14.4.24
  70. Affected versionversion=9.14.4.6
  71. Affected versionversion=9.14.4.7
  72. Affected versionversion=9.15.1.1
  73. Affected versionversion=9.16.1
  74. Affected versionversion=9.16.1.28
  75. Affected versionversion=9.16.2
  76. Affected versionversion=9.16.2.11
  77. Affected versionversion=9.16.2.13
  78. Affected versionversion=9.16.2.14
  79. Affected versionversion=9.16.2.3
  80. Affected versionversion=9.16.2.7
  81. Affected versionversion=9.16.3
  82. Affected versionversion=9.16.3.14
  83. Affected versionversion=9.16.3.15
  84. Affected versionversion=9.16.3.19
  85. Affected versionversion=9.16.3.23
  86. Affected versionversion=9.16.3.3
  87. Affected versionversion=9.16.4
  88. Affected versionversion=9.16.4.14
  89. Affected versionversion=9.16.4.18
  90. Affected versionversion=9.16.4.19
  91. Affected versionversion=9.16.4.27
  92. Affected versionversion=9.16.4.38
  93. Affected versionversion=9.16.4.39
  94. Affected versionversion=9.16.4.42
  95. Affected versionversion=9.16.4.48
  96. Affected versionversion=9.16.4.55
  97. Affected versionversion=9.16.4.57
  98. Affected versionversion=9.16.4.61
  99. Affected versionversion=9.16.4.62
  100. Affected versionversion=9.16.4.9
  101. Affected versionversion=9.17.1
  102. Affected versionversion=9.17.1.10
  103. Affected versionversion=9.17.1.11
  104. Affected versionversion=9.17.1.13
  105. Affected versionversion=9.17.1.15
  106. Affected versionversion=9.17.1.20
  107. Affected versionversion=9.17.1.30
  108. Affected versionversion=9.17.1.33
  109. Affected versionversion=9.17.1.39
  110. Affected versionversion=9.17.1.45
  111. Affected versionversion=9.17.1.46
  112. Affected versionversion=9.17.1.7
  113. Affected versionversion=9.17.1.9
  114. Affected versionversion=9.18.1
  115. Affected versionversion=9.18.1.3
  116. Affected versionversion=9.18.2
  117. Affected versionversion=9.18.2.5
  118. Affected versionversion=9.18.2.7
  119. Affected versionversion=9.18.2.8
  120. Affected versionversion=9.18.3
  121. Affected versionversion=9.18.3.39
  122. Affected versionversion=9.18.3.46
  123. Affected versionversion=9.18.3.53
  124. Affected versionversion=9.18.3.55
  125. Affected versionversion=9.18.3.56
  126. Affected versionversion=9.18.4
  127. Affected versionversion=9.18.4.22
  128. Affected versionversion=9.18.4.24
  129. Affected versionversion=9.18.4.29
  130. Affected versionversion=9.18.4.5
  131. Affected versionversion=9.18.4.8
  132. Affected versionversion=9.19.1
  133. Affected versionversion=9.19.1.12
  134. Affected versionversion=9.19.1.18
  135. Affected versionversion=9.19.1.22
  136. Affected versionversion=9.19.1.24
  137. Affected versionversion=9.19.1.27
  138. Affected versionversion=9.19.1.28
  139. Affected versionversion=9.19.1.31
  140. Affected versionversion=9.19.1.37
  141. Affected versionversion=9.19.1.38
  142. Affected versionversion=9.19.1.5
  143. Affected versionversion=9.19.1.9
  144. Affected versionversion=9.20.1
  145. Affected versionversion=9.20.1.5
  146. Affected versionversion=9.20.2
  147. Affected versionversion=9.20.2.10
  148. Affected versionversion=9.20.2.21
  149. Affected versionversion=9.20.2.22
  150. Affected versionversion=9.20.3
  151. Affected versionversion=9.8.2.28
  152. Affected versionversion=9.8.2.33
  153. Affected versionversion=9.8.2.35
  154. Affected versionversion=9.8.2.38
  155. Affected versionversion=9.8.2.45
  156. Affected versionversion=9.8.3
  157. Affected versionversion=9.8.3.11
  158. Affected versionversion=9.8.3.14
  159. Affected versionversion=9.8.3.16
  160. Affected versionversion=9.8.3.18
  161. Affected versionversion=9.8.3.21
  162. Affected versionversion=9.8.3.26
  163. Affected versionversion=9.8.3.29
  164. Affected versionversion=9.8.3.8
  165. Affected versionversion=9.8.4
  166. Affected versionversion=9.8.4.10
  167. Affected versionversion=9.8.4.12
  168. Affected versionversion=9.8.4.15
  169. Affected versionversion=9.8.4.17
  170. Affected versionversion=9.8.4.20
  171. Affected versionversion=9.8.4.22
  172. Affected versionversion=9.8.4.25
  173. Affected versionversion=9.8.4.26
  174. Affected versionversion=9.8.4.29
  175. Affected versionversion=9.8.4.3
  176. Affected versionversion=9.8.4.32
  177. Affected versionversion=9.8.4.33
  178. Affected versionversion=9.8.4.34
  179. Affected versionversion=9.8.4.35
  180. Affected versionversion=9.8.4.39
  181. Affected versionversion=9.8.4.40
  182. Affected versionversion=9.8.4.41
  183. Affected versionversion=9.8.4.43
  184. Affected versionversion=9.8.4.44
  185. Affected versionversion=9.8.4.45
  186. Affected versionversion=9.8.4.46
  187. Affected versionversion=9.8.4.48
  188. Affected versionversion=9.8.4.7
  189. Affected versionversion=9.8.4.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=9.12.1; version=9.12.1.2; version=9.12.1.3; version=9.12.2; version=9.12.2.1; version=9.12.2.4; version=9.12.2.5; version=9.12.2.9; version=9.12.3; version=9.12.3.12; version=9.12.3.2; version=9.12.3.7; version=9.12.3.9; version=9.12.4; version=9.12.4.10; version=9.12.4.13; version=9.12.4.18; version=9.12.4.2; 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=9.12.4.4; 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=9.14.1; version=9.14.1.10; version=9.14.1.15; version=9.14.1.19; version=9.14.1.30; version=9.14.1.6; version=9.14.2; version=9.14.2.13; version=9.14.2.15; version=9.14.2.4; version=9.14.2.8; version=9.14.3; version=9.14.3.1; version=9.14.3.11; version=9.14.3.13; version=9.14.3.15; version=9.14.3.18; version=9.14.3.9; version=9.14.4; 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; version=9.15.1.1; 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=9.16.4.18; 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=9.16.4.9; 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=9.18.4.5; 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=9.8.2.28; version=9.8.2.33; version=9.8.2.35; version=9.8.2.38; version=9.8.2.45; version=9.8.3; version=9.8.3.11; version=9.8.3.14; version=9.8.3.16; version=9.8.3.18; version=9.8.3.21; version=9.8.3.26; version=9.8.3.29; version=9.8.3.8; version=9.8.4; version=9.8.4.10; version=9.8.4.12; version=9.8.4.15; version=9.8.4.17; version=9.8.4.20; version=9.8.4.22; version=9.8.4.25; version=9.8.4.26; version=9.8.4.29; version=9.8.4.3; version=9.8.4.32; version=9.8.4.33; version=9.8.4.34; version=9.8.4.35; version=9.8.4.39; version=9.8.4.40; version=9.8.4.41; version=9.8.4.43; version=9.8.4.44; version=9.8.4.45; version=9.8.4.46; version=9.8.4.48; version=9.8.4.7; version=9.8.4.8
ClamAV · Cisco Firepower Threat Defenseversion=6.2.3.1; version=6.2.3.10; version=6.2.3.11; version=6.2.3.12; version=6.2.3.13; version=6.2.3.14; version=6.2.3.15; version=6.2.3.16; version=6.2.3.17; version=6.2.3.18; version=6.2.3.2; version=6.2.3.3; version=6.2.3.4; version=6.2.3.5; version=6.2.3.6; version=6.2.3.7; version=6.2.3.8; version=6.2.3.9; version=6.4.0; version=6.4.0.1; version=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=6.4.0.2; version=6.4.0.3; version=6.4.0.4; version=6.4.0.5; version=6.4.0.6; version=6.4.0.7; version=6.4.0.8; version=6.4.0.9; version=6.6.0; version=6.6.0.1; version=6.6.1; version=6.6.3; version=6.6.4; version=6.6.5; version=6.6.5.1; version=6.6.5.2; version=6.6.7; version=6.6.7.1; version=6.6.7.2; 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=7.1.0; 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=7.2.2; 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=7.3.0; 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

Published CVSS scores

8.6CiscoCVSS: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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
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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