Background exploitation KEV catalog
CVE-2017-6743

Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability

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…

CheckOps priority index
5.6/10 Patch within 7 days
Severity8.8
Probability1.1
Exploitation3/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 10.9% higher than 95.9% of CVEs
CVSS 3.0 8.8 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:
Exploited for 1,706 days 03 Mar 2022
CISA due date 24 Mar 2022 for US federal agencies

Exploitation probability EPSS · FIRST

05010026 Sep05 Oct15 Oct24 Oct02 Nov
EPSS probability (%)Percentile among all CVEs

Exploitation signals 3 / 5

  • KEV catalog (CISA)03 Mar 2022
  • Exploited in EUVD (ENISA)03 Mar 2022
  • Used by ransomwareno
  • EPSS above 10 %10.9%
  • No account, over the networkno

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Description ENISA EUVD

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.

Affected products

IOSUniversal ProductIOS and IOS XE Software
Affected versions
  • 12.3(4)XG1
  • 15.6(3)M0a
  • 12.4(25b)
  • 12.2(13)ZH10
  • 12.3(6a)
  • 12.4(13c)
  • 15.1(3)SVD1
  • 12.4(23)
  • 15.2(2)E5b
  • 15.0(1)M5
  • 15.5(3)M
  • 12.3(10d)
Weaknesses (CWE)

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

  1. Published

  2. Exploitation reported (ENISA)

  3. Added to the KEV catalog

  4. CISA remediation due date

  5. EPSS peak: 10.9%

References

Other exploited vulnerabilities from the same vendor

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  • CVE-2026-76519Cisco Secure Email Gateway Relative Path Traversal Vulnerability
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  • CVE-2026-76504Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability
    7.5 · Actively exploited
  • CVE-2026-76460Cisco Identity Services Engine Incorrect Use of Privileged APIs Vulnerability
    8.7 · Actively exploited
  • CVE-2026-76461Cisco Secure Email Gateway SQL Injection Vulnerability
    7.2 · Actively exploited
  • CVE-2026-20079Cisco Firewall Management Center Authentication Bypass Using an Alternate Path or Channel Vulnerability
    9.1 · Actively exploited

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Sources: CISA KEV · ENISA EUVD · FIRST EPSS · OSV. Public data aggregated by CheckOps, updated automatically. Source texts remain the property of their authors. All exploited vulnerabilities