No exploitation reported

CVE-2017-6766

No exploitation reported by the sources we read.

Published2017-08-07
WeaknessCWE-310

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2017-08-0706:29CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2017-6766?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2017-6766?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Cisco firesight system software

Branch	Affected	Fixed in	Source
5.4	= 5.4.0	no fix published	NVD
5.4	= 5.4.1	no fix published	NVD
6.0	= 6.0.0	no fix published	NVD
6.1	= 6.1.0	no fix published	NVD
6.2	= 6.2.0	no fix published	NVD
6.2	= 6.2.1	no fix published	NVD
6.2	= 6.2.2	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

quickview.cloudapps.cisco.comVendor Advisory
tools.cisco.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.07.5read 2026-10-23
NVDCVSS 2.05read 2026-10-23
CNAweakness (CWE)CWE-310read 2026-10-23
FIRST EPSSEPSS score1.3 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Published: 2017-08-07
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2017-6766?

Is CVE-2017-6766 actively exploited?

Active exploitation of CVE-2017-6766 has not been confirmed. Its EPSS score was 1.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2017-6766?

CVE-2017-6766 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

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