CVE-2025-20136Network attack vector

Device reload via NAT DNS inspection loop

Published Aug 14, 2025 · Updated Aug 14, 2025

Denial of service in Cisco ASA and FTD Software allows remote attackers to reload affected devices through crafted DNS packets. The IPv4 and IPv6 NAT DNS inspection function enters an infinite loop while processing a packet that matches a static NAT rule. Exploitation requires DNS inspection and NAT44, NAT64, or NAT46 to be enabled, and a successful packet interrupts service by forcing a device reload.

CVSS severity8.6
High
EPSS probability0.61%
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

Denial of service in Cisco ASA and FTD Software allows remote attackers to reload affected devices through crafted DNS packets. The IPv4 and IPv6 NAT DNS inspection function enters an infinite loop while processing a packet that matches a static NAT rule. Exploitation requires DNS inspection and NAT44, NAT64, or NAT46 to be enabled, and a successful packet interrupts service by forcing a device reload.

The record

CVE
CVE-2025-20136
Published
Aug 14, 2025
Updated
Aug 14, 2025
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-835, T1499.004
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=9.16.4.67
  101. Affected versionversion=9.16.4.70
  102. Affected versionversion=9.16.4.71
  103. Affected versionversion=9.16.4.9
  104. Affected versionversion=9.17.1
  105. Affected versionversion=9.17.1.10
  106. Affected versionversion=9.17.1.11
  107. Affected versionversion=9.17.1.13
  108. Affected versionversion=9.17.1.15
  109. Affected versionversion=9.17.1.20
  110. Affected versionversion=9.17.1.30
  111. Affected versionversion=9.17.1.33
  112. Affected versionversion=9.17.1.39
  113. Affected versionversion=9.17.1.45
  114. Affected versionversion=9.17.1.46
  115. Affected versionversion=9.17.1.7
  116. Affected versionversion=9.17.1.9
  117. Affected versionversion=9.18.1
  118. Affected versionversion=9.18.1.3
  119. Affected versionversion=9.18.2
  120. Affected versionversion=9.18.2.5
  121. Affected versionversion=9.18.2.7
  122. Affected versionversion=9.18.2.8
  123. Affected versionversion=9.18.3
  124. Affected versionversion=9.18.3.39
  125. Affected versionversion=9.18.3.46
  126. Affected versionversion=9.18.3.53
  127. Affected versionversion=9.18.3.55
  128. Affected versionversion=9.18.3.56
  129. Affected versionversion=9.18.4
  130. Affected versionversion=9.18.4.22
  131. Affected versionversion=9.18.4.24
  132. Affected versionversion=9.18.4.29
  133. Affected versionversion=9.18.4.34
  134. Affected versionversion=9.18.4.40
  135. Affected versionversion=9.18.4.47
  136. Affected versionversion=9.18.4.5
  137. Affected versionversion=9.18.4.8
  138. Affected versionversion=9.19.1
  139. Affected versionversion=9.19.1.12
  140. Affected versionversion=9.19.1.18
  141. Affected versionversion=9.19.1.22
  142. Affected versionversion=9.19.1.24
  143. Affected versionversion=9.19.1.27
  144. Affected versionversion=9.19.1.28
  145. Affected versionversion=9.19.1.31
  146. Affected versionversion=9.19.1.37
  147. Affected versionversion=9.19.1.38
  148. Affected versionversion=9.19.1.5
  149. Affected versionversion=9.19.1.9
  150. Affected versionversion=9.20.1
  151. Affected versionversion=9.20.1.5
  152. Affected versionversion=9.20.2
  153. Affected versionversion=9.20.2.10
  154. Affected versionversion=9.20.2.21
  155. Affected versionversion=9.20.2.22
  156. Affected versionversion=9.20.3
  157. Affected versionversion=9.20.3.4
  158. Affected versionversion=9.22.1.1
  159. Affected versionversion=9.22.1.2
  160. Affected versionversion=9.8.1
  161. Affected versionversion=9.8.1.5
  162. Affected versionversion=9.8.1.7
  163. Affected versionversion=9.8.2
  164. Affected versionversion=9.8.2.14
  165. Affected versionversion=9.8.2.15
  166. Affected versionversion=9.8.2.17
  167. Affected versionversion=9.8.2.20
  168. Affected versionversion=9.8.2.24
  169. Affected versionversion=9.8.2.26
  170. Affected versionversion=9.8.2.28
  171. Affected versionversion=9.8.2.33
  172. Affected versionversion=9.8.2.35
  173. Affected versionversion=9.8.2.38
  174. Affected versionversion=9.8.2.45
  175. Affected versionversion=9.8.2.8
  176. Affected versionversion=9.8.3
  177. Affected versionversion=9.8.3.11
  178. Affected versionversion=9.8.3.14
  179. Affected versionversion=9.8.3.16
  180. Affected versionversion=9.8.3.18
  181. Affected versionversion=9.8.3.21
  182. Affected versionversion=9.8.3.26
  183. Affected versionversion=9.8.3.29
  184. Affected versionversion=9.8.3.8
  185. Affected versionversion=9.8.4
  186. Affected versionversion=9.8.4.10
  187. Affected versionversion=9.8.4.12
  188. Affected versionversion=9.8.4.15
  189. Affected versionversion=9.8.4.17
  190. Affected versionversion=9.8.4.20
  191. Affected versionversion=9.8.4.22
  192. Affected versionversion=9.8.4.25
  193. Affected versionversion=9.8.4.26
  194. Affected versionversion=9.8.4.29
  195. Affected versionversion=9.8.4.3
  196. Affected versionversion=9.8.4.32
  197. Affected versionversion=9.8.4.33
  198. Affected versionversion=9.8.4.34
  199. Affected versionversion=9.8.4.35
  200. Affected versionversion=9.8.4.39
  201. Affected versionversion=9.8.4.40
  202. Affected versionversion=9.8.4.41
  203. Affected versionversion=9.8.4.43
  204. Affected versionversion=9.8.4.44
  205. Affected versionversion=9.8.4.45
  206. Affected versionversion=9.8.4.46
  207. Affected versionversion=9.8.4.48
  208. Affected versionversion=9.8.4.7
  209. 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=9.16.4.67; version=9.16.4.70; version=9.16.4.71; 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=9.18.4.8; 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=9.22.1.1; version=9.22.1.2; version=9.8.1; version=9.8.1.5; version=9.8.1.7; version=9.8.2; version=9.8.2.14; version=9.8.2.15; version=9.8.2.17; version=9.8.2.20; version=9.8.2.24; version=9.8.2.26; 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=9.8.2.8; 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; version=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=7.0.6.3; 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=7.2.9; 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=7.6.0

Published CVSS scores

8.6CiscoCVSS:3.1/AV:N/AC:L/PR:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

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