basicsecurity.net
Proof, not just disclosure.
Threats / Cisco / CVE-2026-20122
CVE-2026-20122 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Cisco Catalyst SD-WAN Manger vulnerability

Cisco Catalyst SD-WAN Manager allows attackers to upload malicious files via improper API handling, enabling arbitrary file overwrite and privilege escalation to vmanage user level.

Verdict

Today item — known-exploited.

An unauthenticated or low-privileged attacker can exploit insecure file handling in the API interface to upload malicious files, overwrite system files, and escalate privileges. This vulnerability is actively exploited in the wild.

CISA KEV Yes · 2026-04-203EPSS 0.0613 (verify live)4Exploit Weaponized · public PoC5
01

Is it exploitable?

— the evidence, ranked above the score
Exploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
4 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 2026-04-20).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.0613 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Cisco, Catalyst SD-WAN Manger. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-648 CWE-648.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
02

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.

03

Why it matters

— the attack path, told twice: adversary, then board
1

Front door — unauthenticated access narrative 1

Attacker
I identify the SD-WAN Manager API endpoint that accepts file uploads without proper validation.
Business
The organization's SD-WAN infrastructure management layer is exposed to direct compromise.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I craft a malicious file and upload it through the vulnerable API interface to overwrite critical system files.
Business
Attackers gain persistent access to the management plane controlling the entire SD-WAN deployment.
3

Lateral reach — past segmentation narrative 3

Attacker
I leverage the file overwrite capability to escalate my privileges to vmanage user level.
Business
Administrative control of SD-WAN Manager is compromised, enabling network-wide traffic manipulation and data exfiltration.
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’t

Established (cited)

  • KEV listing (CISA)
  • EPSS probability (FIRST)
  • Weaponized exploit available (VulnCheck)
  • 4 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • Public exploit availability
  • 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/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by ciscoCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.