CVE-2023-20108Network attack vector

Unauthenticated service restart via crafted login message

Published Jun 28, 2023 · Updated Aug 2, 2024

Denial of service in Cisco Unified CM IM&P allows remote attackers to restart the XCP Authentication Service with a crafted login message. The service fails to validate user-supplied fields before using a message value for an excessive-size memory allocation, which triggers the restart. No credentials or user interaction are required; the restart blocks new authentication attempts but leaves existing authenticated sessions unaffected.

CVSS severity7.5
High
EPSS probability0.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco Unified CM IM&P allows remote attackers to restart the XCP Authentication Service with a crafted login message. The service fails to validate user-supplied fields before using a message value for an excessive-size memory allocation, which triggers the restart. No credentials or user interaction are required; the restart blocks new authentication attempts but leaves existing authenticated sessions unaffected.

The record

CVE
CVE-2023-20108
Published
Jun 28, 2023
Updated
Aug 2, 2024
Vendor
ClamAV
Product
Cisco Unified Communications Manager IM and Presence Service
Classifications
CWE-770, CWE-789, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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=10.0(1)
  2. Affected versionversion=10.0(1)SU1
  3. Affected versionversion=10.0(1)SU2
  4. Affected versionversion=10.5(1)
  5. Affected versionversion=10.5(1)SU1
  6. Affected versionversion=10.5(1)SU2
  7. Affected versionversion=10.5(1)SU3
  8. Affected versionversion=10.5(2)
  9. Affected versionversion=10.5(2a)
  10. Affected versionversion=10.5(2b)
  11. Affected versionversion=10.5(2)SU1
  12. Affected versionversion=10.5(2)SU2
  13. Affected versionversion=10.5(2)SU2a
  14. Affected versionversion=10.5(2)SU3
  15. Affected versionversion=10.5(2)SU4
  16. Affected versionversion=10.5(2)SU4a
  17. Affected versionversion=11.0(1)
  18. Affected versionversion=11.0(1)SU1
  19. Affected versionversion=11.5(1)
  20. Affected versionversion=11.5(1)SU1
  21. Affected versionversion=11.5(1)SU10
  22. Affected versionversion=11.5(1)SU11
  23. Affected versionversion=11.5(1)SU2
  24. Affected versionversion=11.5(1)SU3
  25. Affected versionversion=11.5(1)SU3a
  26. Affected versionversion=11.5(1)SU4
  27. Affected versionversion=11.5(1)SU5
  28. Affected versionversion=11.5(1)SU5a
  29. Affected versionversion=11.5(1)SU6
  30. Affected versionversion=11.5(1)SU7
  31. Affected versionversion=11.5(1)SU8
  32. Affected versionversion=11.5(1)SU9
  33. Affected versionversion=12.5(1)
  34. Affected versionversion=12.5(1)SU1
  35. Affected versionversion=12.5(1)SU2
  36. Affected versionversion=12.5(1)SU3
  37. Affected versionversion=12.5(1)SU4
  38. Affected versionversion=12.5(1)SU5
  39. Affected versionversion=12.5(1)SU6
  40. Affected versionversion=14
  41. Affected versionversion=14SU1
  42. Affected versionversion=14SU2
  43. Affected versionversion=14SU2a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Unified Communications Manager IM and Presence Serviceversion=10.0(1); version=10.0(1)SU1; version=10.0(1)SU2; version=10.5(1); version=10.5(1)SU1; version=10.5(1)SU2; version=10.5(1)SU3; version=10.5(2); version=10.5(2a); version=10.5(2b); version=10.5(2)SU1; version=10.5(2)SU2; version=10.5(2)SU2a; version=10.5(2)SU3; version=10.5(2)SU4; version=10.5(2)SU4a; version=11.0(1); version=11.0(1)SU1; version=11.5(1); version=11.5(1)SU1; version=11.5(1)SU10; version=11.5(1)SU11; version=11.5(1)SU2; version=11.5(1)SU3; version=11.5(1)SU3a; version=11.5(1)SU4; version=11.5(1)SU5; version=11.5(1)SU5a; version=11.5(1)SU6; version=11.5(1)SU7; version=11.5(1)SU8; version=11.5(1)SU9; version=12.5(1); version=12.5(1)SU1; version=12.5(1)SU2; version=12.5(1)SU3; version=12.5(1)SU4; version=12.5(1)SU5; version=12.5(1)SU6; version=14; version=14SU1; version=14SU2; version=14SU2a

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-770Allocation of Resources Without Limits or Throttling
CWE-789Memory Allocation with Excessive Size Value
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

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Your stack

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