Threats / Cisco / CVE-2025-20393
CVE-2025-20393
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-09-19
Cisco Multiple Products vulnerability
Cisco Secure Email Gateway, Secure Email, AsyncOS Software, and Web Manager appliances contain an improper input validation vulnerability enabling arbitrary command execution with root privileges on affected systems.
Verdict
Today item — known-exploited.
An unauthenticated or low-privileged attacker can exploit improper input validation to execute arbitrary commands with root-level access on vulnerable Cisco email and web management appliances, potentially compromising email infrastructure and administrative systems.
CISA KEV Yes · 2025-12-175EPSS 0.29875 (verify live)6CVSS 103CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
14 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 2025-12-17).
Probability (EPSS)
EPSS 0.29875 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 10 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) · Affected: Cisco, Multiple Products. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · 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 the same day 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 identify and craft malicious input that bypasses validation controls on the appliance interface.
Business
Email security infrastructure becomes a direct attack vector for command injection and system compromise.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I submit the crafted payload to execute arbitrary commands with root privileges on the underlying operating system.
Business
Complete control of the appliance enables data exfiltration, lateral movement, and persistent access to email systems.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistence and pivot to connected networks and systems relying on the compromised appliance.
Business
Organizational email communications, authentication systems, and connected infrastructure face compromise and operational disruption.
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
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
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
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