CVE-2026-20301Network attack vector

Unauthenticated device reboot via malformed XMCP packets

Published Aug 5, 2026 · Updated Aug 5, 2026

Denial of service in XMCP for Cisco IOS and IOS XE Software allows remote attackers to reboot affected devices with malformed packets. The XMCP Server improperly handles a malformed XMCP packet and reloads the device instead of rejecting the input. Exposure requires an affected software release with the XMCP Server feature enabled; no XMCP client username is required, and the consequence is a service-interrupting reboot.

CVSS severity8.6
High
EPSS probability0.33%
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 XMCP for Cisco IOS and IOS XE Software allows remote attackers to reboot affected devices with malformed packets. The XMCP Server improperly handles a malformed XMCP packet and reloads the device instead of rejecting the input. Exposure requires an affected software release with the XMCP Server feature enabled; no XMCP client username is required, and the consequence is a service-interrupting reboot.

The record

CVE
CVE-2026-20301
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
ClamAV
Product
Cisco IOS
Classifications
CWE-606, T1499.004
Attack vector
network
Privileges
unauthenticated

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=15.2(1)SY6
  2. Affected versionversion=15.2(1)SY7
  3. Affected versionversion=15.2(1)SY8
  4. Affected versionversion=15.2(2)E10
  5. Affected versionversion=15.2(2)E10a
  6. Affected versionversion=15.2(2)E10b
  7. Affected versionversion=15.2(2)E10c
  8. Affected versionversion=15.2(2)E8
  9. Affected versionversion=15.2(2)E9
  10. Affected versionversion=15.2(2)E9a
  11. Affected versionversion=15.2(4)E10
  12. Affected versionversion=15.2(4)E10a
  13. Affected versionversion=15.2(4)E10b
  14. Affected versionversion=15.2(4)E10c
  15. Affected versionversion=15.2(4)E10d
  16. Affected versionversion=15.2(4)E10e
  17. Affected versionversion=15.2(4)E6
  18. Affected versionversion=15.2(4)E7
  19. Affected versionversion=15.2(4)E8
  20. Affected versionversion=15.2(4)E9
  21. Affected versionversion=15.2(4)EA7
  22. Affected versionversion=15.2(4)EA8
  23. Affected versionversion=15.2(4)EA9
  24. Affected versionversion=15.2(4)EA9a
  25. Affected versionversion=15.2(6)E1
  26. Affected versionversion=15.2(6)E1a
  27. Affected versionversion=15.2(6)E1s
  28. Affected versionversion=15.2(6)E2
  29. Affected versionversion=15.2(6)E2a
  30. Affected versionversion=15.2(6)E2b
  31. Affected versionversion=15.2(6)E3
  32. Affected versionversion=15.2(7)E
  33. Affected versionversion=15.2(7)E0a
  34. Affected versionversion=15.2(7)E0b
  35. Affected versionversion=15.2(7)E0s
  36. Affected versionversion=15.2(7)E1
  37. Affected versionversion=15.2(7)E10
  38. Affected versionversion=15.2(7)E11
  39. Affected versionversion=15.2(7)E12
  40. Affected versionversion=15.2(7)E13
  41. Affected versionversion=15.2(7)E14
  42. Affected versionversion=15.2(7)E1a
  43. Affected versionversion=15.2(7)E2
  44. Affected versionversion=15.2(7)E2b
  45. Affected versionversion=15.2(7)E3
  46. Affected versionversion=15.2(7)E3k
  47. Affected versionversion=15.2(7)E4
  48. Affected versionversion=15.2(7)E5
  49. Affected versionversion=15.2(7)E6
  50. Affected versionversion=15.2(7)E7
  51. Affected versionversion=15.2(7)E8
  52. Affected versionversion=15.2(7)E9
  53. Affected versionversion=15.2(8)E
  54. Affected versionversion=15.2(8)E1
  55. Affected versionversion=15.2(8)E2
  56. Affected versionversion=15.2(8)E3
  57. Affected versionversion=15.2(8)E4
  58. Affected versionversion=15.2(8)E5
  59. Affected versionversion=15.2(8)E6
  60. Affected versionversion=15.2(8)E7
  61. Affected versionversion=15.2(8)E8
  62. Affected versionversion=15.4(1)SY4
  63. Affected versionversion=15.5(1)SY1
  64. Affected versionversion=15.5(1)SY10
  65. Affected versionversion=15.5(1)SY11
  66. Affected versionversion=15.5(1)SY12
  67. Affected versionversion=15.5(1)SY13
  68. Affected versionversion=15.5(1)SY14
  69. Affected versionversion=15.5(1)SY15
  70. Affected versionversion=15.5(1)SY16
  71. Affected versionversion=15.5(1)SY17
  72. Affected versionversion=15.5(1)SY2
  73. Affected versionversion=15.5(1)SY3
  74. Affected versionversion=15.5(1)SY4
  75. Affected versionversion=15.5(1)SY5
  76. Affected versionversion=15.5(1)SY6
  77. Affected versionversion=15.5(1)SY7
  78. Affected versionversion=15.5(1)SY8
  79. Affected versionversion=15.5(1)SY9
  80. Affected versionversion=15.6(2)SP4
  81. Affected versionversion=15.6(2)SP5
  82. Affected versionversion=15.6(2)SP6
  83. Affected versionversion=15.6(2)SP7
  84. Affected versionversion=15.6(2)SP8
  85. Affected versionversion=15.6(2)SP8a
  86. Affected versionversion=15.6(2)SP9
  87. Affected versionversion=15.7(3)M10
  88. Affected versionversion=15.7(3)M10a
  89. Affected versionversion=15.7(3)M10b
  90. Affected versionversion=15.7(3)M2
  91. Affected versionversion=15.7(3)M3
  92. Affected versionversion=15.7(3)M4
  93. Affected versionversion=15.7(3)M4a
  94. Affected versionversion=15.7(3)M4b
  95. Affected versionversion=15.7(3)M5
  96. Affected versionversion=15.7(3)M6
  97. Affected versionversion=15.7(3)M7
  98. Affected versionversion=15.7(3)M8
  99. Affected versionversion=15.7(3)M9
  100. Affected versionversion=15.8(3)M
  101. Affected versionversion=15.8(3)M0a
  102. Affected versionversion=15.8(3)M0b
  103. Affected versionversion=15.8(3)M1
  104. Affected versionversion=15.8(3)M1a
  105. Affected versionversion=15.8(3)M2
  106. Affected versionversion=15.8(3)M2a
  107. Affected versionversion=15.8(3)M3
  108. Affected versionversion=15.8(3)M3a
  109. Affected versionversion=15.8(3)M3b
  110. Affected versionversion=15.8(3)M4
  111. Affected versionversion=15.8(3)M5
  112. Affected versionversion=15.8(3)M6
  113. Affected versionversion=15.8(3)M7
  114. Affected versionversion=15.8(3)M8
  115. Affected versionversion=15.8(3)M9
  116. Affected versionversion=15.9(3)M
  117. Affected versionversion=15.9(3)M0a
  118. Affected versionversion=15.9(3)M1
  119. Affected versionversion=15.9(3)M10
  120. Affected versionversion=15.9(3)M11
  121. Affected versionversion=15.9(3)M12
  122. Affected versionversion=15.9(3)M13
  123. Affected versionversion=15.9(3)M2
  124. Affected versionversion=15.9(3)M2a
  125. Affected versionversion=15.9(3)M3
  126. Affected versionversion=15.9(3)M3a
  127. Affected versionversion=15.9(3)M3b
  128. Affected versionversion=15.9(3)M4
  129. Affected versionversion=15.9(3)M4a
  130. Affected versionversion=15.9(3)M5
  131. Affected versionversion=15.9(3)M6
  132. Affected versionversion=15.9(3)M6a
  133. Affected versionversion=15.9(3)M6b
  134. Affected versionversion=15.9(3)M7
  135. Affected versionversion=15.9(3)M7a
  136. Affected versionversion=15.9(3)M8
  137. Affected versionversion=15.9(3)M8a
  138. Affected versionversion=15.9(3)M8b
  139. Affected versionversion=15.9(3)M9
  140. Affected versionversion=15.9(3)M9a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco IOSversion=15.2(1)SY6; version=15.2(1)SY7; version=15.2(1)SY8; version=15.2(2)E10; version=15.2(2)E10a; version=15.2(2)E10b; version=15.2(2)E10c; version=15.2(2)E8; version=15.2(2)E9; version=15.2(2)E9a; version=15.2(4)E10; version=15.2(4)E10a; version=15.2(4)E10b; version=15.2(4)E10c; version=15.2(4)E10d; version=15.2(4)E10e; version=15.2(4)E6; version=15.2(4)E7; version=15.2(4)E8; version=15.2(4)E9; version=15.2(4)EA7; version=15.2(4)EA8; version=15.2(4)EA9; version=15.2(4)EA9a; version=15.2(6)E1; version=15.2(6)E1a; version=15.2(6)E1s; version=15.2(6)E2; version=15.2(6)E2a; version=15.2(6)E2b; version=15.2(6)E3; version=15.2(7)E; version=15.2(7)E0a; version=15.2(7)E0b; version=15.2(7)E0s; version=15.2(7)E1; version=15.2(7)E10; version=15.2(7)E11; version=15.2(7)E12; version=15.2(7)E13; version=15.2(7)E14; version=15.2(7)E1a; version=15.2(7)E2; version=15.2(7)E2b; version=15.2(7)E3; version=15.2(7)E3k; version=15.2(7)E4; version=15.2(7)E5; version=15.2(7)E6; version=15.2(7)E7; version=15.2(7)E8; version=15.2(7)E9; version=15.2(8)E; version=15.2(8)E1; version=15.2(8)E2; version=15.2(8)E3; version=15.2(8)E4; version=15.2(8)E5; version=15.2(8)E6; version=15.2(8)E7; version=15.2(8)E8; version=15.4(1)SY4; version=15.5(1)SY1; version=15.5(1)SY10; version=15.5(1)SY11; version=15.5(1)SY12; version=15.5(1)SY13; version=15.5(1)SY14; version=15.5(1)SY15; version=15.5(1)SY16; version=15.5(1)SY17; version=15.5(1)SY2; version=15.5(1)SY3; version=15.5(1)SY4; version=15.5(1)SY5; version=15.5(1)SY6; version=15.5(1)SY7; version=15.5(1)SY8; version=15.5(1)SY9; version=15.6(2)SP4; version=15.6(2)SP5; version=15.6(2)SP6; version=15.6(2)SP7; version=15.6(2)SP8; version=15.6(2)SP8a; version=15.6(2)SP9; version=15.7(3)M10; version=15.7(3)M10a; version=15.7(3)M10b; version=15.7(3)M2; version=15.7(3)M3; version=15.7(3)M4; version=15.7(3)M4a; version=15.7(3)M4b; version=15.7(3)M5; version=15.7(3)M6; version=15.7(3)M7; version=15.7(3)M8; version=15.7(3)M9; version=15.8(3)M; version=15.8(3)M0a; version=15.8(3)M0b; version=15.8(3)M1; version=15.8(3)M1a; version=15.8(3)M2; version=15.8(3)M2a; version=15.8(3)M3; version=15.8(3)M3a; version=15.8(3)M3b; version=15.8(3)M4; version=15.8(3)M5; version=15.8(3)M6; version=15.8(3)M7; version=15.8(3)M8; version=15.8(3)M9; version=15.9(3)M; version=15.9(3)M0a; version=15.9(3)M1; version=15.9(3)M10; version=15.9(3)M11; version=15.9(3)M12; version=15.9(3)M13; version=15.9(3)M2; version=15.9(3)M2a; version=15.9(3)M3; version=15.9(3)M3a; version=15.9(3)M3b; version=15.9(3)M4; version=15.9(3)M4a; version=15.9(3)M5; version=15.9(3)M6; version=15.9(3)M6a; version=15.9(3)M6b; version=15.9(3)M7; version=15.9(3)M7a; version=15.9(3)M8; version=15.9(3)M8a; version=15.9(3)M8b; version=15.9(3)M9; version=15.9(3)M9a
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=16.12.16; 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=17.12.7; version=17.12.7a; version=17.12.7b; 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=17.15.5; version=17.15.5a; 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=17.18.1z; version=17.18.2; version=17.18.3; version=17.18.3a; 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=26.1.1; version=26.1.1a; version=26.2.1ea; version=3.11.10E; version=3.11.11E; version=3.11.12E; version=3.11.13E; version=3.11.14E; version=3.11.3aE; version=3.11.3E; version=3.11.4E; version=3.11.5E; version=3.11.6E; version=3.11.7E; version=3.11.8E; version=3.11.9E; version=3.16.10aS; version=3.16.10bS; version=3.18.8aSP; version=3.18.9SP; version=3.8.10cE; version=3.8.10dE

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 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-606Unchecked Input for Loop Condition
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

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