Threats / Cisco / CVE-2017-6740
CVE-2017-6740
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Cisco IOS and XE Software vulnerability
A vulnerability in the SNMP subsystem of Cisco IOS and IOS XE allows authenticated remote attackers to execute arbitrary code or cause system reboot.
Verdict
Today item — known-exploited.
An authenticated remote attacker can exploit this buffer overflow vulnerability in SNMP to achieve remote code execution or denial of service on affected Cisco devices, with confirmed exploitation in the wild.
CISA KEV Yes · 2022-03-035EPSS 0.10788 (verify live)6CVSS 8.83CISA SSVC Exploitation: active · Automatable: no · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-03).
Probability (EPSS)
EPSS 0.10788 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 8.8 (CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) · Affected: Cisco, IOS and IOS XE Software. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.0, set at disclosure.
Weakness (CWE)
Mapped to CWE-119 Memory Buffer Bounds Error — weakness family: Memory safety.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 1690 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I gain network access and obtain valid SNMP credentials through phishing or credential compromise.
Business
Network perimeter security is compromised, enabling lateral movement to critical infrastructure.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I send a crafted SNMP message to the target device that triggers a buffer overflow in the SNMP subsystem.
Business
Cisco routing and switching infrastructure becomes vulnerable to direct compromise.
3
Lateral reach — past segmentation narrative 3
Attacker
I execute arbitrary code with device privileges or force an uncontrolled system reload.
Business
Network availability is disrupted and attacker gains persistent control of network infrastructure.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05