CVE-2024-20397

Unverified software loading via insecure bootloader settings

Published Dec 4, 2024 · Updated Apr 8, 2025

Improper access control in Cisco NX-OS Software bootloaders allows attackers to bypass image verification and load unverified software. Insecure bootloader settings accept a sequence of bootloader commands that defeats the signature-verification boundary for NX-OS images. Exploitation requires unauthenticated physical device access or local administrative credentials, and successful use replaces trusted code with attacker-selected software.

CVSS severity5.2
Medium
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 access control in Cisco NX-OS Software bootloaders allows attackers to bypass image verification and load unverified software. Insecure bootloader settings accept a sequence of bootloader commands that defeats the signature-verification boundary for NX-OS images. Exploitation requires unauthenticated physical device access or local administrative credentials, and successful use replaces trusted code with attacker-selected software.

The record

CVE
CVE-2024-20397
Published
Dec 4, 2024
Updated
Apr 8, 2025
Vendor
ClamAV
Product
Cisco Unified Computing System (Managed)
Classifications
CWE-284, T1542.003
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 4, 2024CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 2025Record 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=4.0(1a)
  2. Affected versionversion=4.0(1b)
  3. Affected versionversion=4.0(1c)
  4. Affected versionversion=4.0(1d)
  5. Affected versionversion=4.0(2a)
  6. Affected versionversion=4.0(2b)
  7. Affected versionversion=4.0(2d)
  8. Affected versionversion=4.0(2e)
  9. Affected versionversion=4.0(4a)
  10. Affected versionversion=4.0(4b)
  11. Affected versionversion=4.0(4c)
  12. Affected versionversion=4.0(4d)
  13. Affected versionversion=4.0(4e)
  14. Affected versionversion=4.0(4f)
  15. Affected versionversion=4.0(4g)
  16. Affected versionversion=4.0(4h)
  17. Affected versionversion=4.0(4i)
  18. Affected versionversion=4.0(4k)
  19. Affected versionversion=4.0(4l)
  20. Affected versionversion=4.0(4m)
  21. Affected versionversion=4.0(4n)
  22. Affected versionversion=4.0(4o)
  23. Affected versionversion=4.1(1a)
  24. Affected versionversion=4.1(1b)
  25. Affected versionversion=4.1(1c)
  26. Affected versionversion=4.1(1d)
  27. Affected versionversion=4.1(1e)
  28. Affected versionversion=4.1(2a)
  29. Affected versionversion=4.1(2b)
  30. Affected versionversion=4.1(2c)
  31. Affected versionversion=4.1(3a)
  32. Affected versionversion=4.1(3b)
  33. Affected versionversion=4.1(3c)
  34. Affected versionversion=4.1(3d)
  35. Affected versionversion=4.1(3e)
  36. Affected versionversion=4.1(3f)
  37. Affected versionversion=4.1(3h)
  38. Affected versionversion=4.1(3i)
  39. Affected versionversion=4.1(3j)
  40. Affected versionversion=4.1(3k)
  41. Affected versionversion=4.1(3l)
  42. Affected versionversion=4.1(3m)
  43. Affected versionversion=4.1(4a)
  44. Affected versionversion=4.2(1c)
  45. Affected versionversion=4.2(1d)
  46. Affected versionversion=4.2(1f)
  47. Affected versionversion=4.2(1i)
  48. Affected versionversion=4.2(1k)
  49. Affected versionversion=4.2(1l)
  50. Affected versionversion=4.2(1m)
  51. Affected versionversion=4.2(1n)
  52. Affected versionversion=4.2(2a)
  53. Affected versionversion=4.2(2c)
  54. Affected versionversion=4.2(2d)
  55. Affected versionversion=4.2(2e)
  56. Affected versionversion=4.2(3b)
  57. Affected versionversion=4.2(3d)
  58. Affected versionversion=4.2(3e)
  59. Affected versionversion=4.2(3g)
  60. Affected versionversion=4.2(3h)
  61. Affected versionversion=4.2(3i)
  62. Affected versionversion=4.2(3j)
  63. Affected versionversion=4.2(3k)
  64. Affected versionversion=4.2(3l)
  65. Affected versionversion=4.2(3m)
  66. Affected versionversion=4.3(2b)
  67. Affected versionversion=4.3(2c)
  68. Affected versionversion=4.3(2e)
  69. Affected versionversion=4.3(2f)
  70. Affected versionversion=4.3(3a)
  71. Affected versionversion=4.3(3c)

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Unified Computing System (Managed)version=4.0(1a); version=4.0(1b); version=4.0(1c); version=4.0(1d); version=4.0(2a); version=4.0(2b); version=4.0(2d); version=4.0(2e); version=4.0(4a); version=4.0(4b); version=4.0(4c); version=4.0(4d); version=4.0(4e); version=4.0(4f); version=4.0(4g); version=4.0(4h); version=4.0(4i); version=4.0(4k); version=4.0(4l); version=4.0(4m); version=4.0(4n); version=4.0(4o); version=4.1(1a); version=4.1(1b); version=4.1(1c); version=4.1(1d); version=4.1(1e); version=4.1(2a); version=4.1(2b); version=4.1(2c); version=4.1(3a); version=4.1(3b); version=4.1(3c); version=4.1(3d); version=4.1(3e); version=4.1(3f); version=4.1(3h); version=4.1(3i); version=4.1(3j); version=4.1(3k); version=4.1(3l); version=4.1(3m); version=4.1(4a); version=4.2(1c); version=4.2(1d); version=4.2(1f); version=4.2(1i); version=4.2(1k); version=4.2(1l); version=4.2(1m); version=4.2(1n); version=4.2(2a); version=4.2(2c); version=4.2(2d); version=4.2(2e); version=4.2(3b); version=4.2(3d); version=4.2(3e); version=4.2(3g); version=4.2(3h); version=4.2(3i); version=4.2(3j); version=4.2(3k); version=4.2(3l); version=4.2(3m); version=4.3(2b); version=4.3(2c); version=4.3(2e); version=4.3(2f); version=4.3(3a); version=4.3(3c)
ClamAV · Cisco NX-OS Softwareversion=10.1(1); version=10.1(2); version=10.1(2t); version=10.2(1); version=10.2(1q); version=10.2(2); version=10.2(2a); version=10.2(3); version=10.2(3t); version=10.2(3v); version=10.2(4); version=10.2(5); version=10.2(6); version=10.2(7); version=10.2(8); version=10.3(1); version=10.3(2); version=10.3(3); version=10.3(3o); version=10.3(3p); version=10.3(3q); version=10.3(3r); version=10.3(3w); version=10.3(3x); version=10.3(4); version=10.3(4a); version=10.3(4g); version=10.3(4h); version=10.3(5); version=10.3(6); version=10.3(99w); version=10.3(99x); version=10.4(1); version=10.4(2); version=10.4(3); version=10.4(4); version=10.4(4g); version=10.5(1); version=6.0(2)A8(1); version=6.0(2)A8(10); version=6.0(2)A8(10a); version=6.0(2)A8(11); version=6.0(2)A8(11a); version=6.0(2)A8(11b); version=6.0(2)A8(2); version=6.0(2)A8(3); version=6.0(2)A8(4); version=6.0(2)A8(4a); version=6.0(2)A8(5); version=6.0(2)A8(6); version=6.0(2)A8(7); version=6.0(2)A8(7a); version=6.0(2)A8(7b); version=6.0(2)A8(8); version=6.0(2)A8(9); version=7.0(3)F3(1); version=7.0(3)F3(2); version=7.0(3)F3(3); version=7.0(3)F3(3a); version=7.0(3)F3(3c); version=7.0(3)F3(4); version=7.0(3)F3(5); version=7.0(3)I4(1); version=7.0(3)I4(1t); version=7.0(3)I4(2); version=7.0(3)I4(3); version=7.0(3)I4(4); version=7.0(3)I4(5); version=7.0(3)I4(6); version=7.0(3)I4(6t); version=7.0(3)I4(7); version=7.0(3)I4(8); version=7.0(3)I4(8a); version=7.0(3)I4(8b); version=7.0(3)I4(8z); version=7.0(3)I4(9); version=7.0(3)I5(1); version=7.0(3)I5(2); version=7.0(3)I5(3); version=7.0(3)I5(3a); version=7.0(3)I5(3b); version=7.0(3)I6(1); version=7.0(3)I6(2); version=7.0(3)I7(1); version=7.0(3)I7(10); version=7.0(3)I7(2); version=7.0(3)I7(3); version=7.0(3)I7(3z); version=7.0(3)I7(4); version=7.0(3)I7(5); version=7.0(3)I7(5a); version=7.0(3)I7(6); version=7.0(3)I7(6z); version=7.0(3)I7(7); version=7.0(3)I7(8); version=7.0(3)I7(9); version=7.0(3)I7(9w); version=7.0(3)IA7(1); version=7.0(3)IA7(2); version=7.0(3)IC4(4); version=7.0(3)IM7(2); version=7.3(0)D1(1); version=7.3(0)DX(1); version=7.3(0)DY(1); version=7.3(1)D1(1); version=7.3(1)DY(1); version=7.3(2)D1(1); version=7.3(2)D1(1d); version=7.3(2)D1(2); version=7.3(2)D1(3); version=7.3(2)D1(3a); version=7.3(3)D1(1); version=7.3(4)D1(1); version=7.3(5)D1(1); version=7.3(6)D1(1); version=7.3(7)D1(1); version=7.3(8)D1(1); version=7.3(9)D1(1); version=8.1(1); version=8.1(1a); version=8.1(1b); version=8.1(2); version=8.1(2a); version=8.2(1); version=8.2(10); version=8.2(11); version=8.2(2); version=8.2(3); version=8.2(4); version=8.2(5); version=8.2(6); version=8.2(7); version=8.2(7a); version=8.2(8); version=8.2(9); version=8.3(1); version=8.3(2); version=8.4(1); version=8.4(1a); version=8.4(2); version=8.4(2a); version=8.4(2b); version=8.4(2c); version=8.4(2d); version=8.4(2e); version=8.4(2f); version=8.4(3); version=8.4(4); version=8.4(4a); version=8.4(5); version=8.4(6); version=8.4(6a); version=8.4(7); version=8.4(8); version=8.4(9); version=8.5(1); version=9.2(1); version=9.2(1a); version=9.2(2); version=9.2(2t); version=9.2(2v); version=9.2(3); version=9.2(3y); version=9.2(4); version=9.3(1); version=9.3(10); version=9.3(11); version=9.3(12); version=9.3(13); version=9.3(14); version=9.3(1z); version=9.3(2); version=9.3(2a); version=9.3(3); version=9.3(4); version=9.3(5); version=9.3(5w); version=9.3(6); version=9.3(7); version=9.3(7a); version=9.3(7k); version=9.3(8); version=9.3(9); version=9.4(1); version=9.4(1a)
ClamAV · Cisco NX-OS System Software in ACI Modeversion=13.2(10e); version=13.2(10f); version=13.2(10g); version=13.2(1l); version=13.2(1m); version=13.2(2l); version=13.2(2o); version=13.2(3i); version=13.2(3j); version=13.2(3n); version=13.2(3o); version=13.2(3r); version=13.2(3s); version=13.2(41d); version=13.2(4d); version=13.2(4e); version=13.2(5d); version=13.2(5e); version=13.2(5f); version=13.2(6i); version=13.2(7f); version=13.2(7k); version=13.2(8d); version=13.2(9b); version=13.2(9f); version=13.2(9h); version=14.0(1h); version=14.0(2c); version=14.0(3c); version=14.0(3d); version=14.1(1i); version=14.1(1j); version=14.1(1k); version=14.1(1l); version=14.1(2g); version=14.1(2m); version=14.1(2o); version=14.1(2s); version=14.1(2u); version=14.1(2w); version=14.1(2x); version=14.2(1i); version=14.2(1j); version=14.2(1l); version=14.2(2e); version=14.2(2f); version=14.2(2g); version=14.2(3j); version=14.2(3l); version=14.2(3n); version=14.2(3q); version=14.2(4i); version=14.2(4k); version=14.2(4o); version=14.2(4p); version=14.2(5k); version=14.2(5l); version=14.2(5n); version=14.2(6d); version=14.2(6g); version=14.2(6h); version=14.2(6l); version=14.2(6o); version=14.2(7f); version=14.2(7l); version=14.2(7q); version=14.2(7r); version=14.2(7s); version=14.2(7t); version=14.2(7u); version=14.2(7v); version=14.2(7w); version=15.0(1k); version=15.0(1l); version=15.0(2e); version=15.0(2h); version=15.1(1h); version=15.1(2e); version=15.1(3e); version=15.1(4c); version=15.2(1g); version=15.2(2e); version=15.2(2f); version=15.2(2g); version=15.2(2h); version=15.2(3e); version=15.2(3f); version=15.2(3g); version=15.2(4d); version=15.2(4e); version=15.2(4f); version=15.2(5c); version=15.2(5d); version=15.2(5e); version=15.2(6e); version=15.2(6g); version=15.2(6h); version=15.2(7f); version=15.2(7g); version=15.2(8d); version=15.2(8e); version=15.2(8f); version=15.2(8g); version=15.2(8h); version=15.2(8i); version=15.3(1d); version=15.3(2a); version=15.3(2b); version=15.3(2c); version=15.3(2d); version=15.3(2e); version=16.0(1g); version=16.0(1j); version=16.0(2h); version=16.0(2j); version=16.0(3d); version=16.0(3e); version=16.0(3g); version=16.0(4c); version=16.0(5h); version=16.0(5j); version=16.0(6c); version=16.0(7e); version=16.0(8e); version=16.1(1f)

Published CVSS scores

5.2Cisco Systems, Inc.CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N/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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1542.003Pre-OS Boot: Bootkit

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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