CVE-2026-20278Network attack vector

Authenticated device compromise via improper input neutralization

Published Sep 2, 2026 · Updated Sep 3, 2026

Improper neutralization in Cisco IOS XR Software allows remote authenticated users to compromise confidentiality, integrity, or availability. Cisco groups multiple internally found flaws under this CVE, including command and evaluated-code neutralization errors and invalid array, quantity, and offset checks. The highest-scoring underlying flaw requires low privileges and no user interaction, but Cisco has not disclosed the affected functions, input paths, or individual outcomes.

CVSS severity8.8
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper neutralization in Cisco IOS XR Software allows remote authenticated users to compromise confidentiality, integrity, or availability. Cisco groups multiple internally found flaws under this CVE, including command and evaluated-code neutralization errors and invalid array, quantity, and offset checks. The highest-scoring underlying flaw requires low privileges and no user interaction, but Cisco has not disclosed the affected functions, input paths, or individual outcomes.

The record

CVE
CVE-2026-20278
Published
Sep 2, 2026
Updated
Sep 3, 2026
Vendor
ClamAV
Product
Cisco IOS XR Software
Classifications
CWE-707
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 3, 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=24.1.1
  2. Affected versionversion=24.1.2
  3. Affected versionversion=24.2.1
  4. Affected versionversion=24.2.11
  5. Affected versionversion=24.2.2
  6. Affected versionversion=24.2.20
  7. Affected versionversion=24.2.21
  8. Affected versionversion=24.3.1
  9. Affected versionversion=24.3.2
  10. Affected versionversion=24.3.20
  11. Affected versionversion=24.3.30
  12. Affected versionversion=24.4.1
  13. Affected versionversion=24.4.10
  14. Affected versionversion=24.4.15
  15. Affected versionversion=24.4.2
  16. Affected versionversion=24.4.30
  17. Affected versionversion=25.1.1
  18. Affected versionversion=25.1.2
  19. Affected versionversion=25.1.30
  20. Affected versionversion=25.2.1
  21. Affected versionversion=25.2.15
  22. Affected versionversion=25.2.2
  23. Affected versionversion=25.2.30
  24. Affected versionversion=25.3.1
  25. Affected versionversion=25.3.15
  26. Affected versionversion=25.4.1
  27. Affected versionversion=25.4.2
  28. Affected versionversion=25.4.201
  29. Affected versionversion=25.4.30
  30. Affected versionversion=26.1.1
  31. Affected versionversion=26.1.2
  32. Affected versionversion=26.2.1
  33. Affected versionversion=26.2.100
  34. Affected versionversion=26.2.101
  35. Affected versionversion=6.5.25
  36. Affected versionversion=6.5.26
  37. Affected versionversion=6.5.28
  38. Affected versionversion=6.5.29
  39. Affected versionversion=6.5.31
  40. Affected versionversion=6.5.32
  41. Affected versionversion=6.5.33
  42. Affected versionversion=6.5.35
  43. Affected versionversion=6.5.351
  44. Affected versionversion=6.5.352
  45. Affected versionversion=6.5.353
  46. Affected versionversion=6.5.90
  47. Affected versionversion=6.7.1
  48. Affected versionversion=6.7.2
  49. Affected versionversion=6.7.3
  50. Affected versionversion=6.7.35
  51. Affected versionversion=6.7.4
  52. Affected versionversion=6.8.1
  53. Affected versionversion=6.8.2
  54. Affected versionversion=6.9.1
  55. Affected versionversion=6.9.2
  56. Affected versionversion=7.0.0
  57. Affected versionversion=7.0.1
  58. Affected versionversion=7.0.11
  59. Affected versionversion=7.0.12
  60. Affected versionversion=7.0.14
  61. Affected versionversion=7.0.2
  62. Affected versionversion=7.0.90
  63. Affected versionversion=7.10.1
  64. Affected versionversion=7.10.2
  65. Affected versionversion=7.1.1
  66. Affected versionversion=7.11.1
  67. Affected versionversion=7.11.2
  68. Affected versionversion=7.11.21
  69. Affected versionversion=7.1.15
  70. Affected versionversion=7.1.2
  71. Affected versionversion=7.1.25
  72. Affected versionversion=7.1.3
  73. Affected versionversion=7.2.0
  74. Affected versionversion=7.2.1
  75. Affected versionversion=7.2.12
  76. Affected versionversion=7.2.2
  77. Affected versionversion=7.3.1
  78. Affected versionversion=7.3.15
  79. Affected versionversion=7.3.16
  80. Affected versionversion=7.3.2
  81. Affected versionversion=7.3.27
  82. Affected versionversion=7.3.3
  83. Affected versionversion=7.3.4
  84. Affected versionversion=7.3.5
  85. Affected versionversion=7.3.6
  86. Affected versionversion=7.4.1
  87. Affected versionversion=7.4.15
  88. Affected versionversion=7.4.16
  89. Affected versionversion=7.4.2
  90. Affected versionversion=7.5.1
  91. Affected versionversion=7.5.12
  92. Affected versionversion=7.5.2
  93. Affected versionversion=7.5.3
  94. Affected versionversion=7.5.4
  95. Affected versionversion=7.5.5
  96. Affected versionversion=7.5.52
  97. Affected versionversion=7.6.1
  98. Affected versionversion=7.6.15
  99. Affected versionversion=7.6.2
  100. Affected versionversion=7.6.3
  101. Affected versionversion=7.7.1
  102. Affected versionversion=7.7.2
  103. Affected versionversion=7.7.21
  104. Affected versionversion=7.8.1
  105. Affected versionversion=7.8.12
  106. Affected versionversion=7.8.2
  107. Affected versionversion=7.8.22
  108. Affected versionversion=7.8.23
  109. Affected versionversion=7.9.1
  110. Affected versionversion=7.9.2
  111. Affected versionversion=7.9.21

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco IOS XR Softwareversion=24.1.1; version=24.1.2; version=24.2.1; version=24.2.11; version=24.2.2; version=24.2.20; version=24.2.21; version=24.3.1; version=24.3.2; version=24.3.20; version=24.3.30; version=24.4.1; version=24.4.10; version=24.4.15; version=24.4.2; version=24.4.30; version=25.1.1; version=25.1.2; version=25.1.30; version=25.2.1; version=25.2.15; version=25.2.2; version=25.2.30; version=25.3.1; version=25.3.15; version=25.4.1; version=25.4.2; version=25.4.201; version=25.4.30; version=26.1.1; version=26.1.2; version=26.2.1; version=26.2.100; version=26.2.101; version=6.5.25; version=6.5.26; version=6.5.28; version=6.5.29; version=6.5.31; version=6.5.32; version=6.5.33; version=6.5.35; version=6.5.351; version=6.5.352; version=6.5.353; version=6.5.90; version=6.7.1; version=6.7.2; version=6.7.3; version=6.7.35; version=6.7.4; version=6.8.1; version=6.8.2; version=6.9.1; version=6.9.2; version=7.0.0; version=7.0.1; version=7.0.11; version=7.0.12; version=7.0.14; version=7.0.2; version=7.0.90; version=7.10.1; version=7.10.2; version=7.1.1; version=7.11.1; version=7.11.2; version=7.11.21; version=7.1.15; version=7.1.2; version=7.1.25; version=7.1.3; version=7.2.0; version=7.2.1; version=7.2.12; version=7.2.2; version=7.3.1; version=7.3.15; version=7.3.16; version=7.3.2; version=7.3.27; version=7.3.3; version=7.3.4; version=7.3.5; version=7.3.6; version=7.4.1; version=7.4.15; version=7.4.16; version=7.4.2; version=7.5.1; version=7.5.12; version=7.5.2; version=7.5.3; version=7.5.4; version=7.5.5; version=7.5.52; version=7.6.1; version=7.6.15; version=7.6.2; version=7.6.3; version=7.7.1; version=7.7.2; version=7.7.21; version=7.8.1; version=7.8.12; version=7.8.2; version=7.8.22; version=7.8.23; version=7.9.1; version=7.9.2; version=7.9.21

Published CVSS scores

8.8Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-707Improper Neutralization

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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