CVE-2026-20338Network attack vector

Scanning process crash via ZIP record double-free

Published Aug 7, 2026 · Updated Aug 7, 2026

Double-free in the ZIP parser in Cisco Secure Endpoint allows remote attackers to terminate the ClamAV scanning process with a crafted archive. The ZIP local-header indexing merge shallow-copies original_filename pointers from source catalogs into a combined catalog, allowing both cleanup paths to free the same allocation. No authentication or user interaction is required; the resulting process termination interrupts scanning without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free in the ZIP parser in Cisco Secure Endpoint allows remote attackers to terminate the ClamAV scanning process with a crafted archive. The ZIP local-header indexing merge shallow-copies original_filename pointers from source catalogs into a combined catalog, allowing both cleanup paths to free the same allocation. No authentication or user interaction is required; the resulting process termination interrupts scanning without reported data disclosure or modification.

The record

CVE
CVE-2026-20338
Published
Aug 7, 2026
Updated
Aug 7, 2026
Vendor
ClamAV
Product
Cisco Secure Endpoint
Classifications
CWE-415, 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

7.5Cisco Systems, Inc.CVSS: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 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-415Double Free
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

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Your stack

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