CVE-2024-20436Network attack vector

Device reload via HTTP null dereference

Published Sep 25, 2024 · Updated Sep 25, 2024

Denial of service in Cisco IOS XE Software's HTTP Server feature allows remote attackers to reload devices via crafted HTTP traffic. Requests for specific URLs reach a code path that dereferences a null pointer, forcing the affected device to reload and interrupt service. Exploitation is unauthenticated but requires both HTTP Server and Telephony Service to be enabled; disabled active session modules prevent exposure on the corresponding protocol.

CVSS severity8.6
High
EPSS probability0.86%
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 IOS XE Software's HTTP Server feature allows remote attackers to reload devices via crafted HTTP traffic. Requests for specific URLs reach a code path that dereferences a null pointer, forcing the affected device to reload and interrupt service. Exploitation is unauthenticated but requires both HTTP Server and Telephony Service to be enabled; disabled active session modules prevent exposure on the corresponding protocol.

The record

CVE
CVE-2024-20436
Published
Sep 25, 2024
Updated
Sep 25, 2024
Vendor
ClamAV
Product
Cisco IOS XE Software
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 25, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 2024Record 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=16.10.1
  2. Affected versionversion=16.10.1a
  3. Affected versionversion=16.10.1b
  4. Affected versionversion=16.10.1e
  5. Affected versionversion=16.10.1s
  6. Affected versionversion=16.10.2
  7. Affected versionversion=16.10.3
  8. Affected versionversion=16.11.1
  9. Affected versionversion=16.11.1a
  10. Affected versionversion=16.11.1b
  11. Affected versionversion=16.11.1s
  12. Affected versionversion=16.11.2
  13. Affected versionversion=16.12.1
  14. Affected versionversion=16.12.1a
  15. Affected versionversion=16.12.1c
  16. Affected versionversion=16.12.1s
  17. Affected versionversion=16.12.2
  18. Affected versionversion=16.12.2s
  19. Affected versionversion=16.12.3
  20. Affected versionversion=16.12.3s
  21. Affected versionversion=16.12.4
  22. Affected versionversion=16.12.4a
  23. Affected versionversion=16.12.5
  24. Affected versionversion=16.12.6
  25. Affected versionversion=16.12.7
  26. Affected versionversion=16.12.8
  27. Affected versionversion=16.2.1
  28. Affected versionversion=16.2.2
  29. Affected versionversion=16.3.1
  30. Affected versionversion=16.3.10
  31. Affected versionversion=16.3.11
  32. Affected versionversion=16.3.1a
  33. Affected versionversion=16.3.2
  34. Affected versionversion=16.3.3
  35. Affected versionversion=16.3.4
  36. Affected versionversion=16.3.5
  37. Affected versionversion=16.3.6
  38. Affected versionversion=16.3.7
  39. Affected versionversion=16.3.8
  40. Affected versionversion=16.3.9
  41. Affected versionversion=16.4.1
  42. Affected versionversion=16.4.2
  43. Affected versionversion=16.4.3
  44. Affected versionversion=16.5.1
  45. Affected versionversion=16.5.1b
  46. Affected versionversion=16.5.2
  47. Affected versionversion=16.5.3
  48. Affected versionversion=16.6.1
  49. Affected versionversion=16.6.10
  50. Affected versionversion=16.6.2
  51. Affected versionversion=16.6.3
  52. Affected versionversion=16.6.4
  53. Affected versionversion=16.6.5
  54. Affected versionversion=16.6.6
  55. Affected versionversion=16.6.7
  56. Affected versionversion=16.6.8
  57. Affected versionversion=16.6.9
  58. Affected versionversion=16.7.1
  59. Affected versionversion=16.7.2
  60. Affected versionversion=16.7.3
  61. Affected versionversion=16.8.1
  62. Affected versionversion=16.8.1s
  63. Affected versionversion=16.8.2
  64. Affected versionversion=16.8.3
  65. Affected versionversion=16.9.1
  66. Affected versionversion=16.9.1s
  67. Affected versionversion=16.9.2
  68. Affected versionversion=16.9.3
  69. Affected versionversion=16.9.4
  70. Affected versionversion=16.9.5
  71. Affected versionversion=16.9.6
  72. Affected versionversion=16.9.7
  73. Affected versionversion=16.9.8
  74. Affected versionversion=17.10.1
  75. Affected versionversion=17.10.1a
  76. Affected versionversion=17.10.1b
  77. Affected versionversion=17.1.1
  78. Affected versionversion=17.11.1
  79. Affected versionversion=17.11.1a
  80. Affected versionversion=17.1.1s
  81. Affected versionversion=17.1.1t
  82. Affected versionversion=17.12.1
  83. Affected versionversion=17.12.1a
  84. Affected versionversion=17.1.3
  85. Affected versionversion=17.2.1
  86. Affected versionversion=17.2.1r
  87. Affected versionversion=17.2.1v
  88. Affected versionversion=17.2.2
  89. Affected versionversion=17.2.3
  90. Affected versionversion=17.3.1
  91. Affected versionversion=17.3.1a
  92. Affected versionversion=17.3.2
  93. Affected versionversion=17.3.3
  94. Affected versionversion=17.3.4
  95. Affected versionversion=17.3.4a
  96. Affected versionversion=17.3.5
  97. Affected versionversion=17.3.6
  98. Affected versionversion=17.3.7
  99. Affected versionversion=17.3.8
  100. Affected versionversion=17.3.8a
  101. Affected versionversion=17.4.1
  102. Affected versionversion=17.4.1a
  103. Affected versionversion=17.4.1b
  104. Affected versionversion=17.4.2
  105. Affected versionversion=17.5.1
  106. Affected versionversion=17.5.1a
  107. Affected versionversion=17.6.1
  108. Affected versionversion=17.6.1a
  109. Affected versionversion=17.6.2
  110. Affected versionversion=17.6.3
  111. Affected versionversion=17.6.3a
  112. Affected versionversion=17.6.4
  113. Affected versionversion=17.6.5
  114. Affected versionversion=17.6.5a
  115. Affected versionversion=17.6.6
  116. Affected versionversion=17.6.6a
  117. Affected versionversion=17.7.1
  118. Affected versionversion=17.7.1a
  119. Affected versionversion=17.7.2
  120. Affected versionversion=17.8.1
  121. Affected versionversion=17.8.1a
  122. Affected versionversion=17.9.1
  123. Affected versionversion=17.9.1a
  124. Affected versionversion=17.9.2
  125. Affected versionversion=17.9.2a
  126. Affected versionversion=17.9.3
  127. Affected versionversion=17.9.3a
  128. Affected versionversion=17.9.4
  129. Affected versionversion=17.9.4a
  130. Affected versionversion=3.10.0s
  131. Affected versionversion=3.10.0S
  132. Affected versionversion=3.10.10s
  133. Affected versionversion=3.10.10S
  134. Affected versionversion=3.10.1s
  135. Affected versionversion=3.10.1S
  136. Affected versionversion=3.10.2s
  137. Affected versionversion=3.10.2S
  138. Affected versionversion=3.10.2ts
  139. Affected versionversion=3.10.2tS
  140. Affected versionversion=3.10.3s
  141. Affected versionversion=3.10.3S
  142. Affected versionversion=3.10.4s
  143. Affected versionversion=3.10.4S
  144. Affected versionversion=3.10.5s
  145. Affected versionversion=3.10.5S
  146. Affected versionversion=3.10.6s
  147. Affected versionversion=3.10.6S
  148. Affected versionversion=3.10.7s
  149. Affected versionversion=3.10.7S
  150. Affected versionversion=3.10.8as
  151. Affected versionversion=3.10.8aS
  152. Affected versionversion=3.10.8s
  153. Affected versionversion=3.10.8S
  154. Affected versionversion=3.10.9s
  155. Affected versionversion=3.10.9S
  156. Affected versionversion=3.11.0s
  157. Affected versionversion=3.11.0S
  158. Affected versionversion=3.11.1s
  159. Affected versionversion=3.11.1S
  160. Affected versionversion=3.11.2s
  161. Affected versionversion=3.11.2S
  162. Affected versionversion=3.11.3s
  163. Affected versionversion=3.11.3S
  164. Affected versionversion=3.11.4s
  165. Affected versionversion=3.11.4S
  166. Affected versionversion=3.12.0s
  167. Affected versionversion=3.12.0S
  168. Affected versionversion=3.12.1s
  169. Affected versionversion=3.12.1S
  170. Affected versionversion=3.12.2s
  171. Affected versionversion=3.12.2S
  172. Affected versionversion=3.12.3s
  173. Affected versionversion=3.12.3S
  174. Affected versionversion=3.12.4s
  175. Affected versionversion=3.12.4S
  176. Affected versionversion=3.13.0s
  177. Affected versionversion=3.13.0S
  178. Affected versionversion=3.13.10s
  179. Affected versionversion=3.13.10S
  180. Affected versionversion=3.13.1s
  181. Affected versionversion=3.13.1S
  182. Affected versionversion=3.13.2s
  183. Affected versionversion=3.13.2S
  184. Affected versionversion=3.13.3s
  185. Affected versionversion=3.13.3S
  186. Affected versionversion=3.13.4s
  187. Affected versionversion=3.13.4S
  188. Affected versionversion=3.13.5s
  189. Affected versionversion=3.13.5S
  190. Affected versionversion=3.13.6as
  191. Affected versionversion=3.13.6aS
  192. Affected versionversion=3.13.6s
  193. Affected versionversion=3.13.6S
  194. Affected versionversion=3.13.7s
  195. Affected versionversion=3.13.7S
  196. Affected versionversion=3.13.8s
  197. Affected versionversion=3.13.8S
  198. Affected versionversion=3.13.9s
  199. Affected versionversion=3.13.9S
  200. Affected versionversion=3.14.0s
  201. Affected versionversion=3.14.0S
  202. Affected versionversion=3.14.1s
  203. Affected versionversion=3.14.1S
  204. Affected versionversion=3.14.2s
  205. Affected versionversion=3.14.2S
  206. Affected versionversion=3.14.3s
  207. Affected versionversion=3.14.3S
  208. Affected versionversion=3.14.4s
  209. Affected versionversion=3.14.4S
  210. Affected versionversion=3.15.0s
  211. Affected versionversion=3.15.0S
  212. Affected versionversion=3.15.1cs
  213. Affected versionversion=3.15.1cS
  214. Affected versionversion=3.15.1s
  215. Affected versionversion=3.15.1S
  216. Affected versionversion=3.15.2s
  217. Affected versionversion=3.15.2S
  218. Affected versionversion=3.15.3s
  219. Affected versionversion=3.15.3S
  220. Affected versionversion=3.15.4s
  221. Affected versionversion=3.15.4S
  222. Affected versionversion=3.16.0cs
  223. Affected versionversion=3.16.0cS
  224. Affected versionversion=3.16.0s
  225. Affected versionversion=3.16.0S
  226. Affected versionversion=3.16.10s
  227. Affected versionversion=3.16.10S
  228. Affected versionversion=3.16.1as
  229. Affected versionversion=3.16.1aS
  230. Affected versionversion=3.16.2s
  231. Affected versionversion=3.16.2S
  232. Affected versionversion=3.16.3s
  233. Affected versionversion=3.16.3S
  234. Affected versionversion=3.16.4as
  235. Affected versionversion=3.16.4aS
  236. Affected versionversion=3.16.4bs
  237. Affected versionversion=3.16.4bS
  238. Affected versionversion=3.16.4ds
  239. Affected versionversion=3.16.4dS
  240. Affected versionversion=3.16.5s
  241. Affected versionversion=3.16.5S
  242. Affected versionversion=3.16.6bs
  243. Affected versionversion=3.16.6bS
  244. Affected versionversion=3.16.6s
  245. Affected versionversion=3.16.6S
  246. Affected versionversion=3.16.7as
  247. Affected versionversion=3.16.7aS
  248. Affected versionversion=3.16.7bs
  249. Affected versionversion=3.16.7bS
  250. Affected versionversion=3.16.7s
  251. Affected versionversion=3.16.7S
  252. Affected versionversion=3.16.8s
  253. Affected versionversion=3.16.8S
  254. Affected versionversion=3.16.9s
  255. Affected versionversion=3.16.9S
  256. Affected versionversion=3.17.0s
  257. Affected versionversion=3.17.0S
  258. Affected versionversion=3.17.1s
  259. Affected versionversion=3.17.1S
  260. Affected versionversion=3.17.2s
  261. Affected versionversion=3.17.2S
  262. Affected versionversion=3.17.3s
  263. Affected versionversion=3.17.3S
  264. Affected versionversion=3.17.4s
  265. Affected versionversion=3.17.4S
  266. Affected versionversion=3.18.2asp
  267. Affected versionversion=3.18.2aSP
  268. Affected versionversion=3.9.0as
  269. Affected versionversion=3.9.0aS
  270. Affected versionversion=3.9.1s
  271. Affected versionversion=3.9.1S
  272. Affected versionversion=3.9.2s
  273. Affected versionversion=3.9.2S

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco IOS XE Softwareversion=16.10.1; version=16.10.1a; version=16.10.1b; version=16.10.1e; version=16.10.1s; version=16.10.2; version=16.10.3; version=16.11.1; version=16.11.1a; version=16.11.1b; version=16.11.1s; version=16.11.2; version=16.12.1; version=16.12.1a; version=16.12.1c; version=16.12.1s; version=16.12.2; version=16.12.2s; version=16.12.3; version=16.12.3s; version=16.12.4; version=16.12.4a; version=16.12.5; version=16.12.6; version=16.12.7; version=16.12.8; version=16.2.1; version=16.2.2; version=16.3.1; version=16.3.10; version=16.3.11; version=16.3.1a; version=16.3.2; version=16.3.3; version=16.3.4; version=16.3.5; version=16.3.6; version=16.3.7; version=16.3.8; version=16.3.9; version=16.4.1; version=16.4.2; version=16.4.3; version=16.5.1; version=16.5.1b; version=16.5.2; version=16.5.3; version=16.6.1; version=16.6.10; version=16.6.2; version=16.6.3; version=16.6.4; version=16.6.5; version=16.6.6; version=16.6.7; version=16.6.8; version=16.6.9; version=16.7.1; version=16.7.2; version=16.7.3; version=16.8.1; version=16.8.1s; version=16.8.2; version=16.8.3; version=16.9.1; version=16.9.1s; version=16.9.2; version=16.9.3; version=16.9.4; version=16.9.5; version=16.9.6; version=16.9.7; version=16.9.8; version=17.10.1; version=17.10.1a; version=17.10.1b; version=17.1.1; version=17.11.1; version=17.11.1a; version=17.1.1s; version=17.1.1t; version=17.12.1; version=17.12.1a; version=17.1.3; version=17.2.1; version=17.2.1r; version=17.2.1v; version=17.2.2; version=17.2.3; version=17.3.1; version=17.3.1a; version=17.3.2; version=17.3.3; version=17.3.4; version=17.3.4a; version=17.3.5; version=17.3.6; version=17.3.7; version=17.3.8; version=17.3.8a; version=17.4.1; version=17.4.1a; version=17.4.1b; version=17.4.2; version=17.5.1; version=17.5.1a; version=17.6.1; version=17.6.1a; version=17.6.2; version=17.6.3; version=17.6.3a; version=17.6.4; version=17.6.5; version=17.6.5a; version=17.6.6; version=17.6.6a; version=17.7.1; version=17.7.1a; version=17.7.2; version=17.8.1; version=17.8.1a; version=17.9.1; version=17.9.1a; version=17.9.2; version=17.9.2a; version=17.9.3; version=17.9.3a; version=17.9.4; version=17.9.4a; version=3.10.0s; version=3.10.0S; version=3.10.10s; version=3.10.10S; version=3.10.1s; version=3.10.1S; version=3.10.2s; version=3.10.2S; version=3.10.2ts; version=3.10.2tS; version=3.10.3s; version=3.10.3S; version=3.10.4s; version=3.10.4S; version=3.10.5s; version=3.10.5S; version=3.10.6s; version=3.10.6S; version=3.10.7s; version=3.10.7S; version=3.10.8as; version=3.10.8aS; version=3.10.8s; version=3.10.8S; version=3.10.9s; version=3.10.9S; version=3.11.0s; version=3.11.0S; version=3.11.1s; version=3.11.1S; version=3.11.2s; version=3.11.2S; version=3.11.3s; version=3.11.3S; version=3.11.4s; version=3.11.4S; version=3.12.0s; version=3.12.0S; version=3.12.1s; version=3.12.1S; version=3.12.2s; version=3.12.2S; version=3.12.3s; version=3.12.3S; version=3.12.4s; version=3.12.4S; version=3.13.0s; version=3.13.0S; version=3.13.10s; version=3.13.10S; version=3.13.1s; version=3.13.1S; version=3.13.2s; version=3.13.2S; version=3.13.3s; version=3.13.3S; version=3.13.4s; version=3.13.4S; version=3.13.5s; version=3.13.5S; version=3.13.6as; version=3.13.6aS; version=3.13.6s; version=3.13.6S; version=3.13.7s; version=3.13.7S; version=3.13.8s; version=3.13.8S; version=3.13.9s; version=3.13.9S; version=3.14.0s; version=3.14.0S; version=3.14.1s; version=3.14.1S; version=3.14.2s; version=3.14.2S; version=3.14.3s; version=3.14.3S; version=3.14.4s; version=3.14.4S; version=3.15.0s; version=3.15.0S; version=3.15.1cs; version=3.15.1cS; version=3.15.1s; version=3.15.1S; version=3.15.2s; version=3.15.2S; version=3.15.3s; version=3.15.3S; version=3.15.4s; version=3.15.4S; version=3.16.0cs; version=3.16.0cS; version=3.16.0s; version=3.16.0S; version=3.16.10s; version=3.16.10S; version=3.16.1as; version=3.16.1aS; version=3.16.2s; version=3.16.2S; version=3.16.3s; version=3.16.3S; version=3.16.4as; version=3.16.4aS; version=3.16.4bs; version=3.16.4bS; version=3.16.4ds; version=3.16.4dS; version=3.16.5s; version=3.16.5S; version=3.16.6bs; version=3.16.6bS; version=3.16.6s; version=3.16.6S; version=3.16.7as; version=3.16.7aS; version=3.16.7bs; version=3.16.7bS; version=3.16.7s; version=3.16.7S; version=3.16.8s; version=3.16.8S; version=3.16.9s; version=3.16.9S; version=3.17.0s; version=3.17.0S; version=3.17.1s; version=3.17.1S; version=3.17.2s; version=3.17.2S; version=3.17.3s; version=3.17.3S; version=3.17.4s; version=3.17.4S; version=3.18.2asp; version=3.18.2aSP; version=3.9.0as; version=3.9.0aS; version=3.9.1s; version=3.9.1S; version=3.9.2s; version=3.9.2S

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/E:X/RL:X/RC:X
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 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-476NULL Pointer Dereference
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

See the directory against your own environment.

Your stack

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