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CVE-2026-20122

Cisco Catalyst SD-WAN Manager Arbitrary File Overwrite Vulnerability

Exploited in the wild. In CISA KEV since 2026‑04‑20. A vendor fix is available.

CVSS 3.15.4MediumEPSS percentile98th25% chance in 30 daysCISA KEVListedsince 2026-04-20, due 2026-04-23
Public exploit: 0 sourcesFixVendor fixNo build named by the sources

Published Updated Sources: CVE.org, NVD, BDU

NVD CVE.org

What to do

The vendor has published a fix. Version details are below where the sources state them.

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

A vulnerability in the API of Cisco Catalyst SD-WAN Manager could allow an authenticated, remote attacker to overwrite arbitrary files on the local file system. To exploit this vulnerability, the attacker must have valid read-only credentials with API access on the affected system. This vulnerability is due to improper file handling on the API interface of an affected system. An attacker could exploit this vulnerability by uploading a malicious file on the local file system. A successful exploit could allow the attacker to overwrite arbitrary files on the affected system and gain vmanage user privileges.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS98th
Public exploit
CISA KEV
CISA KEV

Listed as exploited in the wild since 2026-04-20.

US federal agencies must remediate by 2026-04-23.

Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s “Hunt & Hardening Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.
Public exploits

0 sources with a proof of concept or module.

Exploit links, PoCs and Metasploit modules after sign-in
EPSS

25% chance of exploitation activity in the next 30 days, which ranks it in the 98th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

8 events over 149 days, from the signal feeds we watch.

  1. EPSS band changelow → moderateepss band change
  2. OpenVAS check added
  3. Patch availablerecord updated
  4. Added to CISA KEV
  5. Publishedweakness classified

Affected products

And 1 more affected product. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Scored 5.4 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required LowRequires basic user-level privileges
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality LowSome restricted information is disclosed, but limited in scope
  • Integrity LowData modification is possible but limited in scope or consequence
  • Availability NoneNo availability impact

Weaknesses

Sources

References in the record

And 2 more references. See all after sign-in

In the news

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We'll flag the next CVE, public exploit or patch for Catalyst SD-WAN Manager, not every advisory. This one: actively exploited.

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