CVE-2021-1285

Service interruption via Ethernet frame error mishandling

Published Nov 18, 2024 · Updated Nov 18, 2024

Resource exhaustion in Cisco UTD Snort IPS Engine Software allows attackers to interrupt service via malicious Ethernet frames. The Snort Ethernet Frame Decoder mishandles error conditions while processing frames, causing available disk space to be exhausted. Exploitation requires adjacent network access and a vulnerable UTD release configured to pass Ethernet frames to Snort; exhaustion can block administrator login or prevent the device from booting, and recovery requires manual intervention.

CVSS severity7.4
High
EPSS probability2.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Resource exhaustion in Cisco UTD Snort IPS Engine Software allows attackers to interrupt service via malicious Ethernet frames. The Snort Ethernet Frame Decoder mishandles error conditions while processing frames, causing available disk space to be exhausted. Exploitation requires adjacent network access and a vulnerable UTD release configured to pass Ethernet frames to Snort; exhaustion can block administrator login or prevent the device from booting, and recovery requires manual intervention.

The record

CVE
CVE-2021-1285
Published
Nov 18, 2024
Updated
Nov 18, 2024
Vendor
ClamAV
Product
Cisco UTD Snort IPS Engine Software
Classifications
CWE-770, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 18, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 18, 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=16.12.1a
  2. Affected versionversion=16.12.2
  3. Affected versionversion=16.12.3
  4. Affected versionversion=16.12.4
  5. Affected versionversion=16.6.1
  6. Affected versionversion=16.6.5
  7. Affected versionversion=16.6.6
  8. Affected versionversion=16.6.7a
  9. Affected versionversion=17.1.1
  10. Affected versionversion=17.2.1r
  11. Affected versionversion=17.3.1a
  12. Affected versionversion=17.3.2
  13. Affected versionversion=Denali-16.3.3
  14. Affected versionversion=Denali-16.3.4
  15. Affected versionversion=Denali-16.3.5
  16. Affected versionversion=Denali-16.3.7
  17. Affected versionversion=Denali-16.3.9
  18. Affected versionversion=Everest-16.6.2
  19. Affected versionversion=Everest-16.6.3
  20. Affected versionversion=Everest-16.6.4
  21. Affected versionversion=Fuji-16.9.2
  22. Affected versionversion=Fuji-16.9.3
  23. Affected versionversion=Fuji-16.9.4
  24. Affected versionversion=Fuji-16.9.5
  25. Affected versionversion=Fuji-16.9.6
  26. Affected versionversion=Fuji-16.9.7

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco UTD Snort IPS Engine Softwareversion=16.12.1a; version=16.12.2; version=16.12.3; version=16.12.4; version=16.6.1; version=16.6.5; version=16.6.6; version=16.6.7a; version=17.1.1; version=17.2.1r; version=17.3.1a; version=17.3.2; version=Denali-16.3.3; version=Denali-16.3.4; version=Denali-16.3.5; version=Denali-16.3.7; version=Denali-16.3.9; version=Everest-16.6.2; version=Everest-16.6.3; version=Everest-16.6.4; version=Fuji-16.9.2; version=Fuji-16.9.3; version=Fuji-16.9.4; version=Fuji-16.9.5; version=Fuji-16.9.6; version=Fuji-16.9.7

Published CVSS scores

7.4Cisco Systems, Inc.CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
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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