Threats / Cisco / CVE-2017-6663

CVE-2017-6663 · EUVD no mirror located · GCVE no mirror located Verified 2026-09-19

Cisco IOS and XE Software vulnerability

A vulnerability in the Autonomic Networking feature of Cisco IOS and IOS XE Software allows an unauthenticated, adjacent attacker to cause affected systems to reload, resulting in denial of service.

Verdict

Today item — known-exploited.

An unauthenticated attacker on the adjacent network can trigger a denial-of-service condition by exploiting the Autonomic Networking feature to force system reloads. This vulnerability has been observed in active exploitation.

CISA KEV Yes · 2022-03-03⁴EPSS 0.02117 (verify live)⁵CVSS 6.5 (CISA)³CISA SSVC Exploitation: active · Automatable: no · Impact: partial³

Is it exploitable?

— the evidence, ranked above the score

Reported exploitation

1 independent public report of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.

cisa.gov ↗Confirmed

Exploited in the wild

Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-03).

CISA KEV ↗Confirmed

Probability (EPSS)

EPSS 0.02117 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.

FIRST EPSS ↗High

Severity / affected

CVSS 6.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) · Affected: Cisco, IOS and IOS XE Software. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.

CISA-ADP ↗Reported

CISA SSVC (triage disposition)

Exploitation: active · Automatable: no · Technical Impact: partialCISA'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.

CISA-ADP ↗Reported

Currency of the record

CISA added this to its KEV catalog 1669 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.

CISA KEV ↗CVE.org ↗Reported

Who’s exploiting it?

— attribution turns risk into urgency

Attribution 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.

Why it matters

— the attack path, told twice: adversary, then board

Front door — unauthenticated access narrative 1

Attacker

I craft a malicious message targeting the Autonomic Networking feature on an adjacent network segment.

Business

Network availability is disrupted as affected Cisco devices reload unexpectedly.

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker

I send the crafted packet without authentication to trigger a reload condition on autonomic nodes.

Business

Critical infrastructure or service continuity is compromised during the outage window.

Lateral reach — past segmentation narrative 3

Attacker

I repeat the attack to maintain persistent denial of service across the affected network.

Business

Operational costs increase due to incident response, recovery efforts, and potential SLA breaches.

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.

Coverage & confidence

— what we know, and what we don’t

Established (cited)

KEV listing (CISA)

EPSS probability (FIRST)

1 reported-exploitation source(s)

CVSS 6.5 — CISA-assigned (CVE.org ADP)

CISA SSVC triage disposition (CVE.org ADP)

Catalogued by cisco (CNA)

Coverage gaps — stated, not hidden

No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.

EPSS & exposure are time-varying; verify live at the source.

Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.

No finder is named in the public CVE record or the scanned vendor advisory — attribution scoped to the sources checked.

Disclosure & credit²

Catalogued by ciscoCNA

Credited with finding itNo finder is named in the public CVE record or the scanned vendor advisory — attribution scoped to the sources checked.

Found an error? Propose a correction.

A correction is a cited counter-claim — it must cite a source, gets reviewed by a second human, and is never auto-applied. See the correction convention and our identity npub1j7gt9ky7sfcrjn8jjee6693dkzvk4rahs0fk2suu7968dfns62zs3mqm3y.

With JavaScript off: publish a signed kind 1111 Nostr event tagging ["r", "https://basicsecurity.net/threat/cve-2017-6663.html"], ["v", "sha256:5ad61ef264a1fcfcad4e1f513cc891aa016be38e7de8566dc79e8d49c115c807"] (the record version), plus ["src", "<your source URL>"] and ["t", "correction"], per the correction convention. Our identity: npub1j7gt9ky7sfcrjn8jjee6693dkzvk4rahs0fk2suu7968dfns62zs3mqm3y. Cite-or-die: an event with no src is a coverage finding, not a proposal.