CVE-2020-3283Network attack vector

Device reload via SSL/TLS buffer underrun

Published May 6, 2020 · Updated Nov 15, 2024

Denial of service in Cisco Firepower Threat Defense before 6.4.0.9 allows remote attackers to reload Firepower 1000 devices. A crafted SSL/TLS message triggers faulty communication between internal functions, causing a buffer underrun that crashes the handler. Exposure requires a Firepower 1000 appliance with a feature such as AnyConnect or clientless SSL VPN enabled to process SSL/TLS messages.

CVSS severity8.6
High
EPSS probability1.96%
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 Firepower Threat Defense before 6.4.0.9 allows remote attackers to reload Firepower 1000 devices. A crafted SSL/TLS message triggers faulty communication between internal functions, causing a buffer underrun that crashes the handler. Exposure requires a Firepower 1000 appliance with a feature such as AnyConnect or clientless SSL VPN enabled to process SSL/TLS messages.

The record

CVE
CVE-2020-3283
Published
May 6, 2020
Updated
Nov 15, 2024
Vendor
ClamAV
Product
Cisco Firepower Threat Defense
Classifications
CWE-119, CWE-787, T1498
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 6, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Firepower Threat Defenseversion=n/a

Published CVSS scores

8.6NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
8.6CiscoCVSS:3.0/AV:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-787Out-of-bounds Write
T1498Network Denial of Service

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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