The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload. An attacker could exploit these vulnerabilities by sending a crafted SNMP packet to an affected system via IPv4 or IPv6. Only traffic directed to an affected system can be used to exploit these vulnerabilities. The vulnerabilities are due to a buffer overflow condition in the SNMP subsystem of the affected software. The vulnerabilities affect all versions of SNMP - Versions 1, 2c, and 3. To exploit these vulnerabilities via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for the affected system. To exploit these vulnerabilities via SNMP Version 3, the attacker must have user credentials for the affected system. A successful exploit could allow the attacker to execute arbitrary code and obtain full control of the affected system or cause the affected system to reload. Customers are advised to apply the workaround as contained in the Workarounds section below. Fixed software information is available via the Cisco IOS Software Checker. All devices that have enabled SNMP and have not explicitly excluded the affected MIBs or OIDs should be considered vulnerable. There are workarounds that address these vulnerabilities.
Conclusion & alert: CVE-2017-6743 is rated Critical Active Threat (98.6/100): CVSS High severity, with high exploitation likelihood (EPSS 20.36%, 96th percentile). Core evidence: CISA KEV confirms active exploitation (added 2022-03-03) affecting Cisco / IOS and IOS XE Software. a weakness (CWE-119) Unauthenticated remote administrative access may be possible. EPSS rose +6.30% over the last day, indicating growing attacker interest. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.
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: Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability · CISA KEV detail
: 2022-03-03
: 2022-03-24
: Apply updates per vendor instructions.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-04-22 | 14.05% | 20.36% | +6.30% |
| 2 | 2026-04-19 | 10.03% | 14.05% | +4.02% |
| 3 | 2026-04-18 | — | 10.03% | — |
Full EPSS history (25 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 8.8 | 3.1 | HIGH |
|
2.8 | 5.9 | [email protected] |
| 8.8 | 3.0 | HIGH |
|
2.8 | 5.9 | [email protected] |
| 9.0 | 2.0 | HIGH |
|
8.0 | 10.0 | [email protected] |
| URL | Tags |
|---|---|
| https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp | Vendor Advisory |
| http://www.securityfocus.com/bid/99345 | Third Party Advisory VDB Entry |
| http://www.securitytracker.com/id/1038808 | Third Party Advisory VDB Entry |
| https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp | Vendor Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-6743 | US Government Resource |