CVE Intelligence
CISA KEV High Memory corruption

CVE-2017-6742 — Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability

A vulnerability in the SNMP implementation of could allow an authenticated, remote attacker to cause a reload of the affected system or to remotely execute code. An attacker could exploit this vulnerability by sending a crafted SNMP packet to the affected device.  The vulnerability is due to a buffer overflow in the affected code area. The vulnerability affects all versions of SNMP (versions 1, 2c, and 3). The attacker must know the SNMP read only community string (SNMP version 2c or earlier) or the user credentials (SNMPv3). An exploit could allow the attacker to execute arbitrary code and obtain full control of the system or to cause a reload of the affected system. Only traffic directed to the affected system can be used to exploit this vulnerability.

Published Jul 17, 2017 · Updated Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: cisco

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Apr 19, 2023
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • EPSS 21.4% (30-day exploitation probability)+15
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Confirmed
CISA KEV, listed Apr 19, 2023
EPSS FIRST
21.42%
ahead of 98% of scored CVEs · Oct 14, 2026
Affects
Cisco
Cisco IOS XE Software and 3 more
CVSS base
8.8
High · 4 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Active
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

CISA required action CISA

Apply updates per vendor instructions.

US federal deadline: May 10, 2023 — passed 1254 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Cisco Cisco IOS XE Software, Cisco Ios, Cisco Ios Xe…).
  2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. EPSS ahead of 98% of scored CVEs: prioritize it in the patch queue.
  5. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Cisco Cisco IOS XE Software version 3.15.4Sversion 3.16.4bSversion 3.16.4aSversion 3.16.2bSversion 3.16.3Sversion 3.16.0cSversion 3.16.2Sversion 3.16.1aS
and 84 more version 3.16.1Sversion 3.16.0Sversion 3.7.5Eversion 3.7.4Eversion 3.16.5Sversion 3.15.3Sversion 3.15.1cSversion 3.15.2Sversion 3.15.1Sversion 3.15.0Sversion 3.14.4Sversion 3.14.3Sversion 3.14.2Sversion 3.14.1Sversion 3.14.0Sversion 3.6.5bEversion 16.3.3version 3.18.1SPversion 3.18.0SPversion 3.18.1Sversion 3.18.0Sversion 3.18.0aSversion 16.5.1bversion 16.5.1version 16.4.2version 16.4.1version 16.3.4version 16.3.1aversion 3.6.6Eversion 16.3.2version 16.3.1version 16.2.2version 16.2.1version 3.17.3Sversion 3.17.1aSversion 3.17.2Sversion 3.17.1Sversion 3.17.0Sversion 3.16.4dSversion 3.7.4aSversion 3.11.2Sversion 3.11.1Sversion 3.9.0aSversion 3.9.2Sversion 3.9.0Sversion 3.9.1Sversion 3.8.2Sversion 3.8.1Sversion 3.8.0Sversion 3.7.0bSversion 3.7.2tSversion 3.11.0Sversion 3.7.7Sversion 3.7.6Sversion 3.7.5Sversion 3.7.4Sversion 3.7.3Sversion 3.7.2Sversion 3.7.1Sversion 3.7.0Sversion 3.18.1aSPversion 3.18.2aSPversion 3.13.2Sversion 3.6.3Eversion 3.13.7aSversion 3.13.6aSversion 3.13.7Sversion 3.13.6Sversion 3.13.5aSversion 3.13.0aSversion 3.13.2aSversion 3.13.5Sversion 3.13.4Sversion 3.13.3Sversion 3.13.1Sversion 3.13.0Sversion 3.12.4Sversion 3.12.0aSversion 3.12.3Sversion 3.12.2Sversion 3.12.1Sversion 3.12.0Sversion 3.11.4Sversion 3.11.3S
Vulnerable CVE Program (cve.org) e CISA ADP
Cisco Ios ≥ 12.0 and ≤ 12.4≥ 15.0 and ≤ 15.6 Vulnerable NIST National Vulnerability Database
Cisco Ios Xe ≥ 2.2.0 and ≤ 3.17 Vulnerable NIST National Vulnerability Database
IntelliShield Universal Product version N/A Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.8 CVSS 3.1 High 2.8 5.9 nvd@nist.gov via NIST National Vulnerability Database
8.8 CVSS 3.0 High 2.8 5.9 psirt@cisco.com via NIST National Vulnerability Database
8.8 CVSS 3.0 High — — GitHub, Inc. via GitHub Security Advisories
8.8 CVSS 3.0 High — — cisco via CVE Program (cve.org) e CISA ADP
9.0 CVSS 2.0 High 8.0 10.0 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-119 · Buffer Errors (Improper Restriction of Operations within Memory Bounds)

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed
Apr 19, 2023
Federal deadline
May 10, 2023
passed 1254 day(s) ago
Ransomware use
Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

EPSS over time FIRST

Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 21.42%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
  • Hunt retroactively in logs from before Apr 19, 2023 (KEV listing): exploitation may have started earlier.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · cisco/cisco ios xe software, intellishield/universal product
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Affected products added · cisco/ios, cisco/ios xe
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 8.8
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Added to CISA KEV (detected)
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Record created in this database
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • 2023
  • Added to CISA KEV catalog
    Apr 18, 2023 · CISA
  • 2017
  • CVE published
    Jul 17, 2017 · cisco

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

7 on the record

Elsewhere on this site

Cisco
every CVE for this vendor
2023-04
what else CISA listed that month
Memory corruption
same class
CWE-119
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-20301 A vulnerability in the Extensible Messaging Client Protocol (XMCP), also referred to as… Aug 5, 2026
  • CVE-2026-20273 Improper Input Validation in Cisco Ios Xe Aug 5, 2026
  • CVE-2026-20272 Injection in Cisco Ios Xe Aug 5, 2026
  • CVE-2026-20269 As part of Cisco's ongoing commitment to proactive security and product quality, the… Aug 5, 2026
  • CVE-2026-20270 As part of Cisco's ongoing commitment to proactive security and product quality, the… Aug 5, 2026
  • CVE-2026-20271 As part of Cisco's ongoing commitment to proactive security and product quality, the… Aug 5, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2017-6742 is "Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability", rated High. It affects Cisco IOS XE Software (Cisco); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 8.8 describes technical severity. EPSS 21.42% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.