CVE-2026-20023

Adjacent device reboot via malformed OSPF packet parsing

Published Mar 4, 2026 · Updated Mar 4, 2026

Memory corruption in Cisco Secure Firewall ASA and FTD Software allows remote attackers on an adjacent network to reboot affected devices. The OSPF packet parser writes outside allocated memory while processing a crafted protocol packet. The device must be running OSPF and reachable on the adjacent network; successful exploitation interrupts service by forcing a reboot.

CVSS severity6.1
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Cisco Secure Firewall ASA and FTD Software allows remote attackers on an adjacent network to reboot affected devices. The OSPF packet parser writes outside allocated memory while processing a crafted protocol packet. The device must be running OSPF and reachable on the adjacent network; successful exploitation interrupts service by forcing a reboot.

The record

CVE
CVE-2026-20023
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-787, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 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=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=9.16.1
  44. Affected versionversion=9.16.1.28
  45. Affected versionversion=9.16.2
  46. Affected versionversion=9.16.2.11
  47. Affected versionversion=9.16.2.13
  48. Affected versionversion=9.16.2.14
  49. Affected versionversion=9.16.2.3
  50. Affected versionversion=9.16.2.7
  51. Affected versionversion=9.16.3
  52. Affected versionversion=9.16.3.14
  53. Affected versionversion=9.16.3.15
  54. Affected versionversion=9.16.3.19
  55. Affected versionversion=9.16.3.23
  56. Affected versionversion=9.16.3.3
  57. Affected versionversion=9.16.4
  58. Affected versionversion=9.16.4.14
  59. Affected versionversion=9.16.4.19
  60. Affected versionversion=9.16.4.27
  61. Affected versionversion=9.16.4.38
  62. Affected versionversion=9.16.4.39
  63. Affected versionversion=9.16.4.42
  64. Affected versionversion=9.16.4.48
  65. Affected versionversion=9.16.4.55
  66. Affected versionversion=9.16.4.57
  67. Affected versionversion=9.16.4.61
  68. Affected versionversion=9.16.4.62
  69. Affected versionversion=9.16.4.67
  70. Affected versionversion=9.16.4.70
  71. Affected versionversion=9.16.4.71
  72. Affected versionversion=9.16.4.76
  73. Affected versionversion=9.16.4.82
  74. Affected versionversion=9.16.4.84
  75. Affected versionversion=9.16.4.85
  76. Affected versionversion=9.16.4.9
  77. Affected versionversion=9.17.1
  78. Affected versionversion=9.17.1.10
  79. Affected versionversion=9.17.1.11
  80. Affected versionversion=9.17.1.13
  81. Affected versionversion=9.17.1.15
  82. Affected versionversion=9.17.1.20
  83. Affected versionversion=9.17.1.30
  84. Affected versionversion=9.17.1.33
  85. Affected versionversion=9.17.1.39
  86. Affected versionversion=9.17.1.45
  87. Affected versionversion=9.17.1.46
  88. Affected versionversion=9.17.1.7
  89. Affected versionversion=9.17.1.9
  90. Affected versionversion=9.18.1
  91. Affected versionversion=9.18.1.3
  92. Affected versionversion=9.18.2
  93. Affected versionversion=9.18.2.5
  94. Affected versionversion=9.18.2.7
  95. Affected versionversion=9.18.2.8
  96. Affected versionversion=9.18.3
  97. Affected versionversion=9.18.3.39
  98. Affected versionversion=9.18.3.46
  99. Affected versionversion=9.18.3.53
  100. Affected versionversion=9.18.3.55
  101. Affected versionversion=9.18.3.56
  102. Affected versionversion=9.18.4
  103. Affected versionversion=9.18.4.22
  104. Affected versionversion=9.18.4.24
  105. Affected versionversion=9.18.4.29
  106. Affected versionversion=9.18.4.34
  107. Affected versionversion=9.18.4.40
  108. Affected versionversion=9.18.4.47
  109. Affected versionversion=9.18.4.5
  110. Affected versionversion=9.18.4.50
  111. Affected versionversion=9.18.4.52
  112. Affected versionversion=9.18.4.53
  113. Affected versionversion=9.18.4.57
  114. Affected versionversion=9.18.4.66
  115. Affected versionversion=9.18.4.67
  116. Affected versionversion=9.18.4.68
  117. Affected versionversion=9.18.4.8
  118. Affected versionversion=9.19.1
  119. Affected versionversion=9.19.1.12
  120. Affected versionversion=9.19.1.18
  121. Affected versionversion=9.19.1.22
  122. Affected versionversion=9.19.1.24
  123. Affected versionversion=9.19.1.27
  124. Affected versionversion=9.19.1.28
  125. Affected versionversion=9.19.1.31
  126. Affected versionversion=9.19.1.37
  127. Affected versionversion=9.19.1.38
  128. Affected versionversion=9.19.1.42
  129. Affected versionversion=9.19.1.5
  130. Affected versionversion=9.19.1.9
  131. Affected versionversion=9.20.1
  132. Affected versionversion=9.20.1.5
  133. Affected versionversion=9.20.2
  134. Affected versionversion=9.20.2.10
  135. Affected versionversion=9.20.2.21
  136. Affected versionversion=9.20.2.22
  137. Affected versionversion=9.20.3
  138. Affected versionversion=9.20.3.10
  139. Affected versionversion=9.20.3.13
  140. Affected versionversion=9.20.3.16
  141. Affected versionversion=9.20.3.4
  142. Affected versionversion=9.20.3.7
  143. Affected versionversion=9.20.3.9
  144. Affected versionversion=9.20.4
  145. Affected versionversion=9.20.4.10
  146. Affected versionversion=9.20.4.14
  147. Affected versionversion=9.20.4.7
  148. Affected versionversion=9.22.1.1
  149. Affected versionversion=9.22.1.2
  150. Affected versionversion=9.22.1.3
  151. Affected versionversion=9.22.1.6
  152. Affected versionversion=9.22.2.13
  153. Affected versionversion=9.22.2.14
  154. Affected versionversion=9.22.2.9
  155. Affected versionversion=9.23.1
  156. Affected versionversion=9.23.1.13
  157. Affected versionversion=9.23.1.19
  158. Affected versionversion=9.23.1.22
  159. Affected versionversion=9.23.1.7

What conditions does exploitation require?

Attack vectoradjacent
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=9.16.1; 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=9.16.4.19; 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=9.16.4.76; version=9.16.4.82; version=9.16.4.84; version=9.16.4.85; 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=9.18.4.50; version=9.18.4.52; version=9.18.4.53; version=9.18.4.57; version=9.18.4.66; version=9.18.4.67; version=9.18.4.68; 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=9.19.1.42; 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=9.20.3.10; version=9.20.3.13; version=9.20.3.16; version=9.20.3.4; version=9.20.3.7; version=9.20.3.9; version=9.20.4; version=9.20.4.10; version=9.20.4.14; version=9.20.4.7; version=9.22.1.1; version=9.22.1.2; version=9.22.1.3; version=9.22.1.6; version=9.22.2.13; version=9.22.2.14; version=9.22.2.9; version=9.23.1; version=9.23.1.13; version=9.23.1.19; version=9.23.1.22; version=9.23.1.7
ClamAV · Cisco Secure Firewall Threat Defenseversion=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=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=7.0.7; version=7.0.8; version=7.0.8.1; 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=7.2.10; version=7.2.10.2; 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=7.4.2.2; version=7.4.2.3; version=7.4.2.4; version=7.4.3; version=7.6.0; version=7.6.1; version=7.6.2; version=7.6.2.1; version=7.7.0; version=7.7.10.1

Published CVSS scores

6.1Cisco Systems, Inc.CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
6.5NIST NVDCVSS:3.1/AV:A/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
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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