CVE-2026-20337Network attack vector

Scanner crash via ZIP parser out-of-bounds write

Published Aug 7, 2026 · Updated Aug 7, 2026

Out-of-bounds write in the ClamAV ZIP parser in Cisco Secure Endpoint allows remote attackers to terminate scanning with a crafted archive. During ZIP scanning, improper boundary checks allow archive content to write beyond an allocated buffer. No authentication or user interaction is required; submission for scanning crashes the ClamAV process and interrupts malware scanning.

CVSS severity7.5
High
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds write in the ClamAV ZIP parser in Cisco Secure Endpoint allows remote attackers to terminate scanning with a crafted archive. During ZIP scanning, improper boundary checks allow archive content to write beyond an allocated buffer. No authentication or user interaction is required; submission for scanning crashes the ClamAV process and interrupts malware scanning.

The record

CVE
CVE-2026-20337
Published
Aug 7, 2026
Updated
Aug 7, 2026
Vendor
ClamAV
Product
Cisco Secure Endpoint
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

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

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Secure Endpointversion=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=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

7.5CiscoCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo