CVE-2026-20124Network attack vector

Authenticated device reload via malformed SNMP request

Published Aug 5, 2026 · Updated Aug 5, 2026

Denial of service in Cisco IOS XE Software's SNMP subsystem allows remote authenticated users to reload affected devices with malformed requests. The SNMP request parser mishandles errors while processing malformed SNMPv1, v2c, or v3 requests and fails to release a resource after its effective lifetime. SNMP must be enabled, and access requires an SNMPv1 or v2c community string or valid SNMPv3 credentials; exploitation unexpectedly reloads the device and interrupts service.

CVSS severity7.7
High
EPSS probability0.34%
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 SNMP subsystem allows remote authenticated users to reload affected devices with malformed requests. The SNMP request parser mishandles errors while processing malformed SNMPv1, v2c, or v3 requests and fails to release a resource after its effective lifetime. SNMP must be enabled, and access requires an SNMPv1 or v2c community string or valid SNMPv3 credentials; exploitation unexpectedly reloads the device and interrupts service.

The record

CVE
CVE-2026-20124
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
ClamAV
Product
Cisco IOS XE Software
Classifications
CWE-772, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=16.10.1
  2. Affected versionversion=16.10.1a
  3. Affected versionversion=16.10.1b
  4. Affected versionversion=16.10.1c
  5. Affected versionversion=16.10.1d
  6. Affected versionversion=16.10.1e
  7. Affected versionversion=16.10.1f
  8. Affected versionversion=16.10.1g
  9. Affected versionversion=16.10.1s
  10. Affected versionversion=16.10.2
  11. Affected versionversion=16.10.3
  12. Affected versionversion=16.11.1
  13. Affected versionversion=16.11.1a
  14. Affected versionversion=16.11.1b
  15. Affected versionversion=16.11.1c
  16. Affected versionversion=16.11.1s
  17. Affected versionversion=16.11.2
  18. Affected versionversion=16.12.1
  19. Affected versionversion=16.12.10
  20. Affected versionversion=16.12.10a
  21. Affected versionversion=16.12.11
  22. Affected versionversion=16.12.12
  23. Affected versionversion=16.12.13
  24. Affected versionversion=16.12.14
  25. Affected versionversion=16.12.15
  26. Affected versionversion=16.12.1a
  27. Affected versionversion=16.12.1c
  28. Affected versionversion=16.12.1s
  29. Affected versionversion=16.12.1t
  30. Affected versionversion=16.12.1w
  31. Affected versionversion=16.12.1x
  32. Affected versionversion=16.12.1y
  33. Affected versionversion=16.12.1z
  34. Affected versionversion=16.12.1z1
  35. Affected versionversion=16.12.1z2
  36. Affected versionversion=16.12.2
  37. Affected versionversion=16.12.2a
  38. Affected versionversion=16.12.2s
  39. Affected versionversion=16.12.2t
  40. Affected versionversion=16.12.3
  41. Affected versionversion=16.12.3a
  42. Affected versionversion=16.12.3s
  43. Affected versionversion=16.12.4
  44. Affected versionversion=16.12.4a
  45. Affected versionversion=16.12.5
  46. Affected versionversion=16.12.5a
  47. Affected versionversion=16.12.5b
  48. Affected versionversion=16.12.6
  49. Affected versionversion=16.12.6a
  50. Affected versionversion=16.12.7
  51. Affected versionversion=16.12.8
  52. Affected versionversion=16.12.9
  53. Affected versionversion=16.6.10
  54. Affected versionversion=16.6.2
  55. Affected versionversion=16.6.3
  56. Affected versionversion=16.6.4
  57. Affected versionversion=16.6.4a
  58. Affected versionversion=16.6.4s
  59. Affected versionversion=16.6.5
  60. Affected versionversion=16.6.5a
  61. Affected versionversion=16.6.5b
  62. Affected versionversion=16.6.6
  63. Affected versionversion=16.6.7
  64. Affected versionversion=16.6.7a
  65. Affected versionversion=16.6.8
  66. Affected versionversion=16.6.9
  67. Affected versionversion=16.7.1
  68. Affected versionversion=16.7.1a
  69. Affected versionversion=16.7.1b
  70. Affected versionversion=16.7.2
  71. Affected versionversion=16.7.3
  72. Affected versionversion=16.7.4
  73. Affected versionversion=16.8.1
  74. Affected versionversion=16.8.1a
  75. Affected versionversion=16.8.1b
  76. Affected versionversion=16.8.1c
  77. Affected versionversion=16.8.1d
  78. Affected versionversion=16.8.1e
  79. Affected versionversion=16.8.1s
  80. Affected versionversion=16.8.2
  81. Affected versionversion=16.8.3
  82. Affected versionversion=16.9.1
  83. Affected versionversion=16.9.1a
  84. Affected versionversion=16.9.1b
  85. Affected versionversion=16.9.1c
  86. Affected versionversion=16.9.1d
  87. Affected versionversion=16.9.1s
  88. Affected versionversion=16.9.2
  89. Affected versionversion=16.9.2a
  90. Affected versionversion=16.9.2s
  91. Affected versionversion=16.9.3
  92. Affected versionversion=16.9.3a
  93. Affected versionversion=16.9.3h
  94. Affected versionversion=16.9.3s
  95. Affected versionversion=16.9.4
  96. Affected versionversion=16.9.4c
  97. Affected versionversion=16.9.5
  98. Affected versionversion=16.9.5f
  99. Affected versionversion=16.9.6
  100. Affected versionversion=16.9.7
  101. Affected versionversion=16.9.8
  102. Affected versionversion=16.9.8a
  103. Affected versionversion=16.9.8b
  104. Affected versionversion=17.10.1
  105. Affected versionversion=17.10.1a
  106. Affected versionversion=17.10.1b
  107. Affected versionversion=17.1.1
  108. Affected versionversion=17.11.1
  109. Affected versionversion=17.11.1a
  110. Affected versionversion=17.1.1a
  111. Affected versionversion=17.1.1s
  112. Affected versionversion=17.1.1t
  113. Affected versionversion=17.1.2
  114. Affected versionversion=17.12.1
  115. Affected versionversion=17.12.1a
  116. Affected versionversion=17.12.1w
  117. Affected versionversion=17.12.1x
  118. Affected versionversion=17.12.1y
  119. Affected versionversion=17.12.1z
  120. Affected versionversion=17.12.1z1
  121. Affected versionversion=17.12.1z2
  122. Affected versionversion=17.12.1z3
  123. Affected versionversion=17.12.1z4
  124. Affected versionversion=17.12.1z5
  125. Affected versionversion=17.12.1z6
  126. Affected versionversion=17.12.2
  127. Affected versionversion=17.12.2a
  128. Affected versionversion=17.12.3
  129. Affected versionversion=17.12.3a
  130. Affected versionversion=17.12.4
  131. Affected versionversion=17.12.4a
  132. Affected versionversion=17.12.4b
  133. Affected versionversion=17.12.5
  134. Affected versionversion=17.12.5a
  135. Affected versionversion=17.12.5b
  136. Affected versionversion=17.12.5c
  137. Affected versionversion=17.12.5d
  138. Affected versionversion=17.12.6
  139. Affected versionversion=17.12.6a
  140. Affected versionversion=17.12.6b
  141. Affected versionversion=17.1.3
  142. Affected versionversion=17.13.1
  143. Affected versionversion=17.13.1a
  144. Affected versionversion=17.14.1
  145. Affected versionversion=17.14.1a
  146. Affected versionversion=17.15.1
  147. Affected versionversion=17.15.1a
  148. Affected versionversion=17.15.1b
  149. Affected versionversion=17.15.1w
  150. Affected versionversion=17.15.1x
  151. Affected versionversion=17.15.1y
  152. Affected versionversion=17.15.2
  153. Affected versionversion=17.15.2a
  154. Affected versionversion=17.15.2b
  155. Affected versionversion=17.15.2c
  156. Affected versionversion=17.15.3
  157. Affected versionversion=17.15.3a
  158. Affected versionversion=17.15.3b
  159. Affected versionversion=17.15.4
  160. Affected versionversion=17.15.4a
  161. Affected versionversion=17.15.4b
  162. Affected versionversion=17.15.4c
  163. Affected versionversion=17.15.4d
  164. Affected versionversion=17.15.4s1
  165. Affected versionversion=17.16.1
  166. Affected versionversion=17.16.1a
  167. Affected versionversion=17.17.1
  168. Affected versionversion=17.18.1
  169. Affected versionversion=17.18.1a
  170. Affected versionversion=17.18.1w
  171. Affected versionversion=17.18.1x
  172. Affected versionversion=17.18.1y
  173. Affected versionversion=17.18.2
  174. Affected versionversion=17.2.1
  175. Affected versionversion=17.2.1a
  176. Affected versionversion=17.2.1r
  177. Affected versionversion=17.2.1v
  178. Affected versionversion=17.2.2
  179. Affected versionversion=17.2.3
  180. Affected versionversion=17.3.1
  181. Affected versionversion=17.3.1a
  182. Affected versionversion=17.3.1w
  183. Affected versionversion=17.3.1x
  184. Affected versionversion=17.3.1z
  185. Affected versionversion=17.3.2
  186. Affected versionversion=17.3.2a
  187. Affected versionversion=17.3.3
  188. Affected versionversion=17.3.3a
  189. Affected versionversion=17.3.4
  190. Affected versionversion=17.3.4a
  191. Affected versionversion=17.3.4b
  192. Affected versionversion=17.3.4c
  193. Affected versionversion=17.3.5
  194. Affected versionversion=17.3.5a
  195. Affected versionversion=17.3.5b
  196. Affected versionversion=17.3.6
  197. Affected versionversion=17.3.7
  198. Affected versionversion=17.3.8
  199. Affected versionversion=17.3.8a
  200. Affected versionversion=17.4.1
  201. Affected versionversion=17.4.1a
  202. Affected versionversion=17.4.1b
  203. Affected versionversion=17.4.1c
  204. Affected versionversion=17.4.2
  205. Affected versionversion=17.4.2a
  206. Affected versionversion=17.5.1
  207. Affected versionversion=17.5.1a
  208. Affected versionversion=17.6.1
  209. Affected versionversion=17.6.1a
  210. Affected versionversion=17.6.1x
  211. Affected versionversion=17.6.1z
  212. Affected versionversion=17.6.1z1
  213. Affected versionversion=17.6.2
  214. Affected versionversion=17.6.3
  215. Affected versionversion=17.6.3a
  216. Affected versionversion=17.6.4
  217. Affected versionversion=17.6.5
  218. Affected versionversion=17.6.5a
  219. Affected versionversion=17.6.6
  220. Affected versionversion=17.6.6a
  221. Affected versionversion=17.6.7
  222. Affected versionversion=17.6.8
  223. Affected versionversion=17.6.8a
  224. Affected versionversion=17.7.1
  225. Affected versionversion=17.7.1a
  226. Affected versionversion=17.7.1b
  227. Affected versionversion=17.7.2
  228. Affected versionversion=17.8.1
  229. Affected versionversion=17.8.1a
  230. Affected versionversion=17.9.1
  231. Affected versionversion=17.9.1a
  232. Affected versionversion=17.9.1w
  233. Affected versionversion=17.9.1x
  234. Affected versionversion=17.9.1x1
  235. Affected versionversion=17.9.1y
  236. Affected versionversion=17.9.1y1
  237. Affected versionversion=17.9.2
  238. Affected versionversion=17.9.2a
  239. Affected versionversion=17.9.3
  240. Affected versionversion=17.9.3a
  241. Affected versionversion=17.9.4
  242. Affected versionversion=17.9.4a
  243. Affected versionversion=17.9.5
  244. Affected versionversion=17.9.5a
  245. Affected versionversion=17.9.5b
  246. Affected versionversion=17.9.5c
  247. Affected versionversion=17.9.5d
  248. Affected versionversion=17.9.5e
  249. Affected versionversion=17.9.5f
  250. Affected versionversion=17.9.6
  251. Affected versionversion=17.9.6a
  252. Affected versionversion=17.9.7
  253. Affected versionversion=17.9.7a
  254. Affected versionversion=17.9.7b
  255. Affected versionversion=17.9.8
  256. Affected versionversion=17.9.9
  257. Affected versionversion=3.13.10S
  258. Affected versionversion=3.13.9S
  259. Affected versionversion=3.16.10aS
  260. Affected versionversion=3.16.10bS
  261. Affected versionversion=3.16.10S
  262. Affected versionversion=3.16.6bS
  263. Affected versionversion=3.16.7aS
  264. Affected versionversion=3.16.7bS
  265. Affected versionversion=3.16.7S
  266. Affected versionversion=3.16.8S
  267. Affected versionversion=3.16.9S
  268. Affected versionversion=3.18.3aSP
  269. Affected versionversion=3.18.3bSP
  270. Affected versionversion=3.18.3SP
  271. Affected versionversion=3.18.4S
  272. Affected versionversion=3.18.4SP
  273. Affected versionversion=3.18.5SP
  274. Affected versionversion=3.18.6SP
  275. Affected versionversion=3.18.7SP
  276. Affected versionversion=3.18.8aSP
  277. Affected versionversion=3.18.9SP

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco IOS XE Softwareversion=16.10.1; version=16.10.1a; version=16.10.1b; version=16.10.1c; version=16.10.1d; version=16.10.1e; version=16.10.1f; version=16.10.1g; 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=16.11.1c; version=16.11.1s; version=16.11.2; version=16.12.1; version=16.12.10; version=16.12.10a; version=16.12.11; version=16.12.12; version=16.12.13; version=16.12.14; version=16.12.15; version=16.12.1a; version=16.12.1c; version=16.12.1s; version=16.12.1t; version=16.12.1w; version=16.12.1x; version=16.12.1y; version=16.12.1z; version=16.12.1z1; version=16.12.1z2; version=16.12.2; version=16.12.2a; version=16.12.2s; version=16.12.2t; version=16.12.3; version=16.12.3a; version=16.12.3s; version=16.12.4; version=16.12.4a; version=16.12.5; version=16.12.5a; version=16.12.5b; version=16.12.6; version=16.12.6a; version=16.12.7; version=16.12.8; version=16.12.9; version=16.6.10; version=16.6.2; version=16.6.3; version=16.6.4; version=16.6.4a; version=16.6.4s; version=16.6.5; version=16.6.5a; version=16.6.5b; version=16.6.6; version=16.6.7; version=16.6.7a; version=16.6.8; version=16.6.9; version=16.7.1; version=16.7.1a; version=16.7.1b; version=16.7.2; version=16.7.3; version=16.7.4; version=16.8.1; version=16.8.1a; version=16.8.1b; version=16.8.1c; version=16.8.1d; version=16.8.1e; version=16.8.1s; version=16.8.2; version=16.8.3; version=16.9.1; version=16.9.1a; version=16.9.1b; version=16.9.1c; version=16.9.1d; version=16.9.1s; version=16.9.2; version=16.9.2a; version=16.9.2s; version=16.9.3; version=16.9.3a; version=16.9.3h; version=16.9.3s; version=16.9.4; version=16.9.4c; version=16.9.5; version=16.9.5f; version=16.9.6; version=16.9.7; version=16.9.8; version=16.9.8a; version=16.9.8b; 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=17.1.1a; version=17.1.1s; version=17.1.1t; version=17.1.2; version=17.12.1; version=17.12.1a; version=17.12.1w; version=17.12.1x; version=17.12.1y; version=17.12.1z; version=17.12.1z1; version=17.12.1z2; version=17.12.1z3; version=17.12.1z4; version=17.12.1z5; version=17.12.1z6; version=17.12.2; version=17.12.2a; version=17.12.3; version=17.12.3a; version=17.12.4; version=17.12.4a; version=17.12.4b; version=17.12.5; version=17.12.5a; version=17.12.5b; version=17.12.5c; version=17.12.5d; version=17.12.6; version=17.12.6a; version=17.12.6b; version=17.1.3; version=17.13.1; version=17.13.1a; version=17.14.1; version=17.14.1a; version=17.15.1; version=17.15.1a; version=17.15.1b; version=17.15.1w; version=17.15.1x; version=17.15.1y; version=17.15.2; version=17.15.2a; version=17.15.2b; version=17.15.2c; version=17.15.3; version=17.15.3a; version=17.15.3b; version=17.15.4; version=17.15.4a; version=17.15.4b; version=17.15.4c; version=17.15.4d; version=17.15.4s1; version=17.16.1; version=17.16.1a; version=17.17.1; version=17.18.1; version=17.18.1a; version=17.18.1w; version=17.18.1x; version=17.18.1y; version=17.18.2; version=17.2.1; version=17.2.1a; 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=17.3.1w; version=17.3.1x; version=17.3.1z; version=17.3.2; version=17.3.2a; version=17.3.3; version=17.3.3a; version=17.3.4; version=17.3.4a; version=17.3.4b; version=17.3.4c; version=17.3.5; version=17.3.5a; version=17.3.5b; 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=17.4.1c; version=17.4.2; version=17.4.2a; version=17.5.1; version=17.5.1a; version=17.6.1; version=17.6.1a; version=17.6.1x; version=17.6.1z; version=17.6.1z1; 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=17.6.7; version=17.6.8; version=17.6.8a; version=17.7.1; version=17.7.1a; version=17.7.1b; version=17.7.2; version=17.8.1; version=17.8.1a; version=17.9.1; version=17.9.1a; version=17.9.1w; version=17.9.1x; version=17.9.1x1; version=17.9.1y; version=17.9.1y1; 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=17.9.5; version=17.9.5a; version=17.9.5b; version=17.9.5c; version=17.9.5d; version=17.9.5e; version=17.9.5f; version=17.9.6; version=17.9.6a; version=17.9.7; version=17.9.7a; version=17.9.7b; version=17.9.8; version=17.9.9; version=3.13.10S; version=3.13.9S; version=3.16.10aS; version=3.16.10bS; version=3.16.10S; version=3.16.6bS; version=3.16.7aS; version=3.16.7bS; version=3.16.7S; version=3.16.8S; version=3.16.9S; version=3.18.3aSP; version=3.18.3bSP; version=3.18.3SP; version=3.18.4S; version=3.18.4SP; version=3.18.5SP; version=3.18.6SP; version=3.18.7SP; version=3.18.8aSP; version=3.18.9SP

Published CVSS scores

7.7Cisco Systems, Inc.CVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
T1499.004Endpoint Denial of Service: Application 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

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