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CVE-2017-6766

A vulnerability in the Secure Sockets Layer (SSL) Decryption and Inspection feature of Cisco...

7.5 High

CVE-2017-6766 is a high vulnerability (CVSS 7.5) in Cisco Firesight System Software, published August 7, 2017. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.27%, the 70th percentile. No source names a fixed version.

What does this mean?
Severity
7.5 HighCVSS 3.0, NVD
Exploit chance
1.27%EPSS, 70th percentile
Exploitation
None knownNot on CISA’s or ENISA’s lists
Fixed in
No fix listedNo source names one

Description

A vulnerability in the Secure Sockets Layer (SSL) Decryption and Inspection feature of Cisco Firepower System Software 5.4.0, 5.4.1, 6.0.0, 6.1.0, 6.2.0, 6.2.1, and 6.2.2 could allow an unauthenticated, remote attacker to bypass the SSL policy for decrypting and inspecting traffic on an affected system. The vulnerability is due to unexpected interaction with Known Key and Decrypt and Resign configuration settings of SSL policies when the affected software receives unexpected SSL packet headers. An attacker could exploit this vulnerability by sending a crafted SSL packet through an affected device in a valid SSL session. A successful exploit could allow the attacker to bypass the SSL decryption and inspection policy for the affected system, which could allow traffic to flow through the system without being inspected. Cisco Bug IDs: CSCve12652.

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
High
Availability
None

Exploit likelihood

1.27%Up 0.5 points since Apr 14, 2021
90%50%10%1%

Affected products

What each source reports

NVD Score used7.5

A vulnerability in the Secure Sockets Layer (SSL) Decryption and Inspection feature of Cisco Firepower System Software 5.4.0, 5.4.1, 6.0.0, 6.1.0, 6.2.0, 6.2.1, and 6.2.2 could allow an unauthenticated, remote attacker to bypass the SSL policy for decrypting and inspecting traffic on an affected system. The vulnerability is due to unexpected interaction with Known Key and Decrypt and Resign configuration settings of SSL policies when the affected software receives unexpected SSL packet headers. An attacker could exploit this vulnerability by sending a crafted SSL packet through an affected device in a valid SSL session. A successful exploit could allow the attacker to bypass the SSL decryption and inspection policy for the affected system, which could allow traffic to flow through the system without being inspected. Cisco Bug IDs: CSCve12652.

Record
CVE-2017-6766
CVSS 3.0
7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness
CWE-310
Updated
2026-11-02
CVE ListNo score

A vulnerability in the Secure Sockets Layer (SSL) Decryption and Inspection feature of Cisco Firepower System Software 5.4.0, 5.4.1, 6.0.0, 6.1.0, 6.2.0, 6.2.1, and 6.2.2 could allow an unauthenticated, remote attacker to bypass the SSL policy for decrypting and inspecting traffic on an affected system. The vulnerability is due to unexpected interaction with Known Key and Decrypt and Resign configuration settings of SSL policies when the affected software receives unexpected SSL packet headers. An attacker could exploit this vulnerability by sending a crafted SSL packet through an affected device in a valid SSL session. A successful exploit could allow the attacker to bypass the SSL decryption and inspection policy for the affected system, which could allow traffic to flow through the system without being inspected. Cisco Bug IDs: CSCve12652.

Record
CVE-2017-6766
Weakness
CWE-310
Updated
2026-11-02
EUVDEUVD-2017-15820No score

A vulnerability in the Secure Sockets Layer (SSL) Decryption and Inspection feature of Cisco Firepower System Software 5.4.0, 5.4.1, 6.0.0, 6.1.0, 6.2.0, 6.2.1, and 6.2.2 could allow an unauthenticated, remote attacker to bypass the SSL policy for decrypting and inspecting traffic on an affected system. The vulnerability is due to unexpected interaction with Known Key and Decrypt and Resign configuration settings of SSL policies when the affected software receives unexpected SSL packet headers. An attacker could exploit this vulnerability by sending a crafted SSL packet through an affected device in a valid SSL session. A successful exploit could allow the attacker to bypass the SSL decryption and inspection policy for the affected system, which could allow traffic to flow through the system without being inspected. Cisco Bug IDs: CSCve12652.

Record
EUVD-2017-15820
Updated
2026-11-03
GitHub AdvisoriesGHSA-q3pq-v78p-xj7q7.5

A vulnerability in the Secure Sockets Layer (SSL) Decryption and Inspection feature of Cisco...

A vulnerability in the Secure Sockets Layer (SSL) Decryption and Inspection feature of Cisco Firepower System Software 5.4.0, 5.4.1, 6.0.0, 6.1.0, 6.2.0, 6.2.1, and 6.2.2 could allow an unauthenticated, remote attacker to bypass the SSL policy for decrypting and inspecting traffic on an affected system. The vulnerability is due to unexpected interaction with Known Key and Decrypt and Resign configuration settings of SSL policies when the affected software receives unexpected SSL packet headers. An attacker could exploit this vulnerability by sending a crafted SSL packet through an affected device in a valid SSL session. A successful exploit could allow the attacker to bypass the SSL decryption and inspection policy for the affected system, which could allow traffic to flow through the system without being inspected. Cisco Bug IDs: CSCve12652.

Record
GHSA-q3pq-v78p-xj7q
CVSS 3.0
7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02

History

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

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

References

MoveEnter Open