Threats / Cisco / CVE-2025-20352
CVE-2025-20352
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Cisco IOS and XE vulnerability
Stack-based buffer overflow in Cisco IOS and IOS XE SNMP subsystem enables denial of service or remote code execution depending on attacker privilege level.
Verdict
Today item — known-exploited.
A stack-based buffer overflow in the SNMP subsystem of Cisco IOS and IOS XE allows low-privileged attackers to trigger system reload and denial of service, while high-privileged attackers can execute arbitrary code with root access.
CISA KEV Yes · 2025-09-295EPSS 0.38754 (verify live)6CVSS 7.73CISA SSVC Exploitation: active · Automatable: no · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
7 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 2025-09-29).
Probability (EPSS)
EPSS 0.38754 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 7.7 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H) · Affected: Cisco, IOS and IOS XE. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-121 Stack-based Buffer Overflow — 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 5 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 craft a malformed SNMP packet designed to overflow the stack buffer in the SNMP subsystem.
Business
Network infrastructure becomes unstable as affected routers and switches experience unexpected reloads.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I send the malicious SNMP payload to a vulnerable device with low-privilege network access.
Business
Service availability degrades as the device crashes, disrupting routing and connectivity for dependent systems.
3
Lateral reach — past segmentation narrative 3
Attacker
With elevated privileges, I exploit the same buffer overflow to inject and execute arbitrary code at root level.
Business
Complete device compromise allows attackers to establish persistence, intercept traffic, and pivot to other network segments.
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