CVE-2026-20031Network attack vector

Scanning-process crash via UTF-8 splitting error

Published Mar 4, 2026 · Updated Mar 4, 2026

Uncaught exception in Cisco Secure Endpoint connectors allows remote attackers to crash ClamAV scanning with a crafted HTML file. The HTML CSS image parser mishandles errors while splitting UTF-8 strings, allowing malformed input to terminate the scanning process. Exploitation requires the crafted file to reach an affected connector for scanning; the crash delays or prevents further scans without destabilizing the host.

CVSS severity5.3
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncaught exception in Cisco Secure Endpoint connectors allows remote attackers to crash ClamAV scanning with a crafted HTML file. The HTML CSS image parser mishandles errors while splitting UTF-8 strings, allowing malformed input to terminate the scanning process. Exploitation requires the crafted file to reach an affected connector for scanning; the crash delays or prevents further scans without destabilizing the host.

The record

CVE
CVE-2026-20031
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
ClamAV
Product
Cisco Secure Endpoint
Classifications
CWE-248, T1499
Attack vector
network
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=1.1.0
  2. Affected versionversion=1.10.0
  3. Affected versionversion=1.10.1
  4. Affected versionversion=1.10.2
  5. Affected versionversion=1.11.0
  6. Affected versionversion=1.11.1
  7. Affected versionversion=1.12.0
  8. Affected versionversion=1.12.1
  9. Affected versionversion=1.12.2
  10. Affected versionversion=1.12.3
  11. Affected versionversion=1.12.4
  12. Affected versionversion=1.12.5
  13. Affected versionversion=1.12.6
  14. Affected versionversion=1.12.7
  15. Affected versionversion=1.13.0
  16. Affected versionversion=1.13.1
  17. Affected versionversion=1.13.2
  18. Affected versionversion=1.14.0
  19. Affected versionversion=1.14.1
  20. Affected versionversion=1.15.0
  21. Affected versionversion=1.15.1
  22. Affected versionversion=1.15.2
  23. Affected versionversion=1.15.3
  24. Affected versionversion=1.15.4
  25. Affected versionversion=1.15.5
  26. Affected versionversion=1.15.6
  27. Affected versionversion=1.16.0
  28. Affected versionversion=1.16.1
  29. Affected versionversion=1.16.2
  30. Affected versionversion=1.16.3
  31. Affected versionversion=1.17.0
  32. Affected versionversion=1.17.1
  33. Affected versionversion=1.17.2
  34. Affected versionversion=1.18.0
  35. Affected versionversion=1.18.1
  36. Affected versionversion=1.19.0
  37. Affected versionversion=1.20.0
  38. Affected versionversion=1.20.1
  39. Affected versionversion=1.20.2
  40. Affected versionversion=1.20.3
  41. Affected versionversion=1.20.4
  42. Affected versionversion=1.20.5
  43. Affected versionversion=1.20.6
  44. Affected versionversion=1.20.7
  45. Affected versionversion=1.20.8
  46. Affected versionversion=1.21.0
  47. Affected versionversion=1.21.1
  48. Affected versionversion=1.21.2
  49. Affected versionversion=1.21.3
  50. Affected versionversion=1.22.0
  51. Affected versionversion=1.22.1
  52. Affected versionversion=1.22.2
  53. Affected versionversion=1.22.3
  54. Affected versionversion=1.22.4
  55. Affected versionversion=1.23.0
  56. Affected versionversion=1.23.1
  57. Affected versionversion=1.24.0
  58. Affected versionversion=1.24.1
  59. Affected versionversion=1.24.2
  60. Affected versionversion=1.24.3
  61. Affected versionversion=1.24.4
  62. Affected versionversion=1.24.5
  63. Affected versionversion=1.25.0
  64. Affected versionversion=1.25.1
  65. Affected versionversion=1.25.2
  66. Affected versionversion=1.26.0
  67. Affected versionversion=1.26.1
  68. Affected versionversion=1.27.0
  69. Affected versionversion=1.27.1
  70. Affected versionversion=1.27.2
  71. Affected versionversion=1.6.0
  72. Affected versionversion=1.7.0
  73. Affected versionversion=1.8.0
  74. Affected versionversion=1.8.1
  75. Affected versionversion=1.8.4
  76. Affected versionversion=1.9.0
  77. Affected versionversion=1.9.1
  78. Affected versionversion=2.0.0
  79. Affected versionversion=2.0.1
  80. Affected versionversion=2.0.2
  81. Affected versionversion=2.10.0
  82. Affected versionversion=2.10.1
  83. Affected versionversion=2.1.0.14
  84. Affected versionversion=2.11.0
  85. Affected versionversion=2.2.0
  86. Affected versionversion=2.3.0
  87. Affected versionversion=2.4.0
  88. Affected versionversion=2.5.0
  89. Affected versionversion=2.6.0
  90. Affected versionversion=2.7.0
  91. Affected versionversion=2.8.0
  92. Affected versionversion=2.9.0
  93. Affected versionversion=6.0.7
  94. Affected versionversion=6.0.9
  95. Affected versionversion=6.1.5
  96. Affected versionversion=6.1.7
  97. Affected versionversion=6.1.9
  98. Affected versionversion=6.2.1
  99. Affected versionversion=6.2.19
  100. Affected versionversion=6.2.3
  101. Affected versionversion=6.2.5
  102. Affected versionversion=6.2.9
  103. Affected versionversion=6.3.1
  104. Affected versionversion=6.3.3
  105. Affected versionversion=6.3.5
  106. Affected versionversion=6.3.7
  107. Affected versionversion=7.0.5
  108. Affected versionversion=7.1.1
  109. Affected versionversion=7.1.5
  110. Affected versionversion=7.2.11
  111. Affected versionversion=7.2.13
  112. Affected versionversion=7.2.3
  113. Affected versionversion=7.2.5
  114. Affected versionversion=7.2.7
  115. Affected versionversion=7.3.1
  116. Affected versionversion=7.3.13
  117. Affected versionversion=7.3.15
  118. Affected versionversion=7.3.3
  119. Affected versionversion=7.3.5
  120. Affected versionversion=7.3.9
  121. Affected versionversion=7.4.1
  122. Affected versionversion=7.4.1.20425
  123. Affected versionversion=7.4.1.20439
  124. Affected versionversion=7.4.3
  125. Affected versionversion=7.4.3.20679
  126. Affected versionversion=7.4.5
  127. Affected versionversion=7.5.11
  128. Affected versionversion=7.5.1.20813
  129. Affected versionversion=7.5.1.20833
  130. Affected versionversion=7.5.13.21586
  131. Affected versionversion=7.5.13.21598
  132. Affected versionversion=7.5.15.21611
  133. Affected versionversion=7.5.17.21680
  134. Affected versionversion=7.5.19
  135. Affected versionversion=7.5.20
  136. Affected versionversion=7.5.21.21732
  137. Affected versionversion=7.5.3
  138. Affected versionversion=7.5.5
  139. Affected versionversion=7.5.7
  140. Affected versionversion=7.5.9
  141. Affected versionversion=8.0.1.21160
  142. Affected versionversion=8.0.1.21164
  143. Affected versionversion=8.1.3
  144. Affected versionversion=8.1.3.21242
  145. Affected versionversion=8.1.5
  146. Affected versionversion=8.1.5.21322
  147. Affected versionversion=8.1.7
  148. Affected versionversion=8.1.7.21417
  149. Affected versionversion=8.1.7.21512
  150. Affected versionversion=8.1.7.21585
  151. Affected versionversion=8.2.1.21612
  152. Affected versionversion=8.2.1.21650
  153. Affected versionversion=8.2.3.30119
  154. Affected versionversion=8.2.4.30130
  155. Affected versionversion=8.4.0
  156. Affected versionversion=8.4.1.30298
  157. Affected versionversion=8.4.1.30307
  158. Affected versionversion=8.4.2.30317
  159. Affected versionversion=8.4.3
  160. Affected versionversion=8.4.4.30419
  161. Affected versionversion=8.4.4.30467
  162. Affected versionversion=8.4.5.30483

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Secure Endpointversion=1.1.0; version=1.10.0; version=1.10.1; version=1.10.2; version=1.11.0; version=1.11.1; version=1.12.0; version=1.12.1; version=1.12.2; version=1.12.3; version=1.12.4; version=1.12.5; version=1.12.6; version=1.12.7; version=1.13.0; version=1.13.1; version=1.13.2; version=1.14.0; version=1.14.1; version=1.15.0; version=1.15.1; version=1.15.2; version=1.15.3; version=1.15.4; version=1.15.5; version=1.15.6; version=1.16.0; version=1.16.1; version=1.16.2; version=1.16.3; version=1.17.0; version=1.17.1; version=1.17.2; version=1.18.0; version=1.18.1; version=1.19.0; version=1.20.0; version=1.20.1; version=1.20.2; version=1.20.3; version=1.20.4; version=1.20.5; version=1.20.6; version=1.20.7; version=1.20.8; version=1.21.0; version=1.21.1; version=1.21.2; version=1.21.3; version=1.22.0; version=1.22.1; version=1.22.2; version=1.22.3; version=1.22.4; version=1.23.0; version=1.23.1; version=1.24.0; version=1.24.1; version=1.24.2; version=1.24.3; version=1.24.4; version=1.24.5; version=1.25.0; version=1.25.1; version=1.25.2; version=1.26.0; version=1.26.1; version=1.27.0; version=1.27.1; version=1.27.2; version=1.6.0; version=1.7.0; version=1.8.0; version=1.8.1; version=1.8.4; version=1.9.0; version=1.9.1; version=2.0.0; version=2.0.1; version=2.0.2; version=2.10.0; version=2.10.1; version=2.1.0.14; version=2.11.0; version=2.2.0; version=2.3.0; version=2.4.0; version=2.5.0; version=2.6.0; version=2.7.0; version=2.8.0; version=2.9.0; version=6.0.7; version=6.0.9; version=6.1.5; version=6.1.7; version=6.1.9; version=6.2.1; version=6.2.19; version=6.2.3; version=6.2.5; version=6.2.9; version=6.3.1; version=6.3.3; version=6.3.5; version=6.3.7; version=7.0.5; version=7.1.1; version=7.1.5; version=7.2.11; version=7.2.13; version=7.2.3; version=7.2.5; version=7.2.7; version=7.3.1; version=7.3.13; version=7.3.15; version=7.3.3; version=7.3.5; version=7.3.9; version=7.4.1; version=7.4.1.20425; version=7.4.1.20439; version=7.4.3; version=7.4.3.20679; version=7.4.5; version=7.5.11; version=7.5.1.20813; version=7.5.1.20833; version=7.5.13.21586; version=7.5.13.21598; version=7.5.15.21611; version=7.5.17.21680; version=7.5.19; version=7.5.20; version=7.5.21.21732; version=7.5.3; version=7.5.5; version=7.5.7; version=7.5.9; version=8.0.1.21160; version=8.0.1.21164; version=8.1.3; version=8.1.3.21242; version=8.1.5; version=8.1.5.21322; version=8.1.7; version=8.1.7.21417; version=8.1.7.21512; version=8.1.7.21585; version=8.2.1.21612; version=8.2.1.21650; version=8.2.3.30119; version=8.2.4.30130; version=8.4.0; version=8.4.1.30298; version=8.4.1.30307; version=8.4.2.30317; version=8.4.3; version=8.4.4.30419; version=8.4.4.30467; version=8.4.5.30483

Published CVSS scores

5.3Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/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-248Uncaught Exception
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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