CVE Intelligence
CISA KEV High Memory corruption

CVE-2017-6738 — 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 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.

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 · Mar 3, 2022
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • EPSS 10.9% (30-day exploitation probability)+14
  • 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 Mar 3, 2022
EPSS FIRST
10.86%
ahead of 96% of scored CVEs · Oct 14, 2026
Affects
Cisco
Cisco IOS XE Software and 1 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: Mar 24, 2022 — passed 1666 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).
  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 96% 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 3.5.6SQversion 3.8.2Eversion 3.8.1Eversion 3.8.0Eversion 16.2.2version 16.2.1version 16.1.3version 16.1.2
and 83 more version 16.1.1version 3.8.3Eversion 3.5.5SQversion 3.5.4SQversion 3.5.3SQversion 3.5.2SQversion 3.5.1SQversion 3.5.0SQversion 3.7.5Eversion 3.7.4Eversion 16.5.1version 17.11.99SWversion 3.9.2Eversion 3.9.1Eversion 3.9.0Eversion 3.18.2aSPversion 3.18.1aSPversion 16.5.1bversion 16.5.1aversion 3.7.3Eversion 16.4.2version 16.4.1version 16.3.4version 16.3.1aversion 16.3.3version 16.3.2version 16.3.1version 3.8.4Eversion 3.4.3SGversion 3.5.2Eversion 3.5.1Eversion 3.5.0Eversion 3.4.8SGversion 3.4.7SGversion 3.4.6SGversion 3.4.5SGversion 3.4.4SGversion 3.5.3Eversion 3.4.1SGversion 3.4.2SGversion 3.4.0SGversion 3.3.5SEversion 3.3.4SEversion 3.3.3SEversion 3.3.2SEversion 3.3.1SEversion 3.6.5aEversion 3.7.2Eversion 3.7.1Eversion 3.7.0Eversion 3.4.1SQversion 3.4.0SQversion 3.3.1SQversion 3.3.0SQversion 3.6.5bEversion 3.3.0SEversion 3.6.6Eversion 3.6.5Eversion 3.6.4Eversion 3.6.3Eversion 3.6.2Eversion 3.6.2aEversion 3.6.1Eversion 3.6.0Eversion 3.2.0SGversion 3.2.1SGversion 3.2.2SGversion 3.2.3SGversion 3.2.4SGversion 3.2.5SGversion 3.2.6SGversion 3.2.7SGversion 3.2.8SGversion 3.2.9SGversion 3.2.10SGversion 3.2.11SGversion 3.3.0SGversion 3.3.2SGversion 3.3.1SGversion 3.2.0SEversion 3.2.1SEversion 3.2.2SEversion 3.2.3SE
Vulnerable CVE Program (cve.org) e CISA ADP
Cisco Ios version 15.2(5a)E1version 15.2(4)E4version 15.2(5)E2version 15.3(3)Mversion 15.3(3)M1version 15.3(3)M2version 15.3(3)M3version 15.3(3)M5
and 201 more version 15.3(3)M4version 15.3(3)M6version 15.3(3)M7version 15.3(3)M8version 15.3(3)M9version 15.3(3)M8aversion 15.2(4)JNversion 15.0(2)EZversion 15.2(1)EYversion 15.0(2)EJversion 15.0(2)EJ1version 15.2(1)SYversion 15.2(1)SY1version 15.2(1)SY0aversion 15.2(1)SY2version 15.2(2)SYversion 15.2(1)SY1aversion 15.2(2)SY1version 15.2(2)SY2version 15.2(1)SY3version 15.2(1)SY4version 15.2(5)EXversion 15.2(4)JAZ1version 15.0(2)EKversion 15.0(2)EK1version 15.4(1)CGversion 15.4(1)CG1version 15.4(2)CGversion 15.2(2)EBversion 15.2(2)EB1version 15.2(2)EB2version 15.5(1)Tversion 15.5(1)T1version 15.5(2)Tversion 15.5(1)T2version 15.5(1)T3version 15.5(2)T1version 15.5(2)T2version 15.5(2)T3version 15.5(2)T4version 15.5(1)T4version 15.2(2)EAversion 15.2(2)EA1version 15.2(2)EA2version 15.2(3)EAversion 15.2(4)EAversion 15.2(4)EA1version 15.2(2)EA3version 15.2(4)EA3version 15.2(5)EAversion 15.2(4)EA4version 15.2(4)EA5version 15.5(3)Mversion 15.5(3)M1version 15.5(3)M0aversion 15.5(3)M2version 15.5(3)M3version 15.5(3)M4version 15.5(3)M4aversion 15.5(3)M5version 15.3(3)JAA1version 15.0(2)SQDversion 15.0(2)SQD1version 15.0(2)SQD2version 15.0(2)SQD3version 15.0(2)SQD4version 15.0(2)SQD5version 15.0(2)SQD6version 15.6(1)Tversion 15.6(2)Tversion 15.6(1)T0aversion 15.6(1)T1version 15.6(2)T1version 15.6(1)T2version 15.6(2)T2version 15.6(1)T3version 15.3(1)SYversion 15.3(1)SY1version 15.3(1)SY2version 15.6(3)Mversion 15.6(3)M1version 15.6(3)M0aversion 15.6(3)M1bversion 15.6(3)M2version 15.6(3)M2aversion 15.2(4)EC1version 15.2(4)EC2version 15.3(3)JPC5version 15.4(1)SYversion 15.4(1)SY1version 15.4(1)SY2version 15.5(1)SYversion 15.3(3)JPR1version 15.0(2)EYversion 15.0(2)EY1version 15.0(2)EY2version 15.0(2)EY3version 12.2(54)WOversion 15.0(1)SEversion 15.0(2)SEversion 15.0(1)SE1version 15.0(1)SE2version 15.0(1)SE3version 15.0(2)SE1version 15.0(2)SE2version 15.0(2)SE3version 15.0(2)SE4version 15.0(2)SE5version 15.0(2)SE6version 15.0(2)SE7version 15.0(2)SE8version 15.0(2)SE9version 15.0(2)SE10version 15.0(2)SE10aversion 15.1(1)SGversion 15.1(2)SGversion 15.1(1)SG1version 15.1(1)SG2version 15.1(2)SG1version 15.1(2)SG2version 15.1(2)SG3version 15.1(2)SG4version 15.1(2)SG5version 15.1(2)SG6version 15.1(2)SG7version 15.1(2)SG8version 15.2(4)Mversion 15.2(4)M1version 15.2(4)M2version 15.2(4)M4version 15.2(4)M3version 15.2(4)M5version 15.2(4)M8version 15.2(4)M10version 15.2(4)M7version 15.2(4)M6version 15.2(4)M9version 15.2(4)M6aversion 15.2(4)M11version 15.0(2)SGversion 15.0(2)SG1version 15.0(2)SG2version 15.0(2)SG3version 15.0(2)SG4version 15.0(2)SG5version 15.0(2)SG6version 15.0(2)SG7version 15.0(2)SG8version 15.0(2)SG9version 15.0(2)SG10version 15.0(2)SG11version 15.0(2)SG11aversion 15.0(1)EXversion 15.0(2)EXversion 15.0(2)EX1version 15.0(2)EX2version 15.0(2)EX3version 15.0(2)EX4version 15.0(2)EX5version 15.0(2)EX8version 15.0(2a)EX5version 15.0(2)EX10version 15.0(2)EX11version 15.0(2)EX13version 15.0(2)EX12version 15.2(2)GCversion 15.2(3)GCversion 15.2(3)GC1version 15.2(4)GCversion 15.2(4)GC2version 15.2(4)GC3version 15.4(1)Tversion 15.4(2)Tversion 15.4(1)T2version 15.4(1)T1version 15.4(1)T3version 15.4(2)T1version 15.4(2)T3version 15.4(2)T2version 15.4(1)T4version 15.4(2)T4version 15.0(2)EAversion 15.0(2)EA1version 15.2(1)Eversion 15.2(2)Eversion 15.2(1)E1version 15.2(3)Eversion 15.2(1)E2version 15.2(1)E3version 15.2(2)E1version 15.2(4)Eversion 15.2(3)E1version 15.2(2)E2version 15.2(2a)E1version 15.2(2)E3version 15.2(2a)E2version 15.2(3)E2version 15.2(3a)Eversion 15.2(3)E3version 15.2(4)E1version 15.2(2)E4
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
Mar 3, 2022
Federal deadline
Mar 24, 2022
passed 1666 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 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 10.86%

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 Mar 3, 2022 (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/ios, cisco/cisco ios xe software
    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
  • 2022
  • Added to CISA KEV catalog
    Mar 2, 2022 · 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
2022-03
what else CISA listed that month
Memory corruption
same class
CWE-119
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-20125 A vulnerability in the HTTP Server feature of Cisco IOS Software and Cisco IOS XE… Mar 25, 2026
  • CVE-2026-20114 A vulnerability in the Lobby Ambassador web-based management API of Cisco IOS XE… Mar 25, 2026
  • CVE-2026-20115 Cleartext Transmission of Sensitive Information in Cisco Cisco IOS XE Software Mar 25, 2026
  • CVE-2026-20112 Cross-site Scripting (XSS) in Cisco Cisco IOS XE Software Mar 25, 2026
  • CVE-2026-20113 A vulnerability in the web-based Cisco IOx application hosting environment management… Mar 25, 2026
  • CVE-2026-20104 A vulnerability in the bootloader of Cisco IOS XE Software for Cisco Catalyst 9200… Mar 25, 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-2017-6738 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 10.86% 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.

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