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CVE-2019-1691

Cisco Firepower Threat Defense Software SSL or TLS Denial of Service Vulnerability

5.8 Medium

A vulnerability in the detection engine of Cisco Firepower Threat Defense Software could allow an unauthenticated, remote attacker to cause the unexpected restart of the SNORT detection engine, resulting in a denial of service (DoS) condition. The vulnerability is due to the incomplete error handling of the SSL or TLS packet header during the connection establishment. An attacker could exploit this vulnerability by sending a crafted SSL or TLS packet during the connection handshake. An exploit could allow the attacker to cause the SNORT detection engine to unexpectedly restart, resulting in a partial DoS condition while the detection engine restarts. Versions prior to 6.2.3.4 are affected.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

2.27%Up 1.3 points since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 5.8

Cisco Firepower Threat Defense Software SSL or TLS Denial of Service Vulnerability

A vulnerability in the detection engine of Cisco Firepower Threat Defense Software could allow an unauthenticated, remote attacker to cause the unexpected restart of the SNORT detection engine, resulting in a denial of service (DoS) condition. The vulnerability is due to the incomplete error handling of the SSL or TLS packet header during the connection establishment. An attacker could exploit this vulnerability by sending a crafted SSL or TLS packet during the connection handshake. An exploit could allow the attacker to cause the SNORT detection engine to unexpectedly restart, resulting in a partial DoS condition while the detection engine restarts. Versions prior to 6.2.3.4 are affected.

Record
CVE-2019-1691
CVSS 3.0
5.8 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Weakness
CWE-20
Updated
2026-11-02
EUVDEUVD-2019-10248 5.8

A vulnerability in the detection engine of Cisco Firepower Threat Defense Software could allow an unauthenticated, remote attacker to cause the unexpected restart of the SNORT detection engine, resulting in a denial of service (DoS) condition. The vulnerability is due to the incomplete error handling of the SSL or TLS packet header during the connection establishment. An attacker could exploit this vulnerability by sending a crafted SSL or TLS packet during the connection handshake. An exploit could allow the attacker to cause the SNORT detection engine to unexpectedly restart, resulting in a partial DoS condition while the detection engine restarts. Versions prior to 6.2.3.4 are affected.

Record
EUVD-2019-10248
CVSS 3.0
5.8 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Updated
2026-11-03
GitHub AdvisoriesGHSA-95q2-c52x-vr4p 5.8

A vulnerability in the detection engine of Cisco Firepower Threat Defense Software could allow an...

A vulnerability in the detection engine of Cisco Firepower Threat Defense Software could allow an unauthenticated, remote attacker to cause the unexpected restart of the SNORT detection engine, resulting in a denial of service (DoS) condition. The vulnerability is due to the incomplete error handling of the SSL or TLS packet header during the connection establishment. An attacker could exploit this vulnerability by sending a crafted SSL or TLS packet during the connection handshake. An exploit could allow the attacker to cause the SNORT detection engine to unexpectedly restart, resulting in a partial DoS condition while the detection engine restarts. Versions prior to 6.2.3.4 are affected.

Record
GHSA-95q2-c52x-vr4p
CVSS 3.1
5.8 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Weakness
CWE-20, CWE-755
Updated
2026-11-02
NVD 5.8

A vulnerability in the detection engine of Cisco Firepower Threat Defense Software could allow an unauthenticated, remote attacker to cause the unexpected restart of the SNORT detection engine, resulting in a denial of service (DoS) condition. The vulnerability is due to the incomplete error handling of the SSL or TLS packet header during the connection establishment. An attacker could exploit this vulnerability by sending a crafted SSL or TLS packet during the connection handshake. An exploit could allow the attacker to cause the SNORT detection engine to unexpectedly restart, resulting in a partial DoS condition while the detection engine restarts. Versions prior to 6.2.3.4 are affected.

Record
CVE-2019-1691
CVSS 3.1
5.8 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
CVSS 3.0
5.8 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness
CWE-20, CWE-755
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2019-1691 is a medium vulnerability (CVSS 5.8) in Cisco Firepower Threat Defense Software, published February 21, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.27%, the 83rd percentile. No source names a fixed version.

References

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