CVE-2026-20245
CVE-2026-20245 is a security flaw in Cisco Catalyst SD-WAN Manager, Cisco’s business networking equipment. Opening a booby-trapped file can let an attacker run their own code through Cisco Catalyst SD-WAN Manager. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 9 Jun 2026.[1]
Cisco Catalyst SD-WAN Manager is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Cisco has published a fix or advice.
Description
CISA calls it an improper encoding or escaping of output in Cisco Catalyst SD-WAN Manager. In its words: “Cisco Catalyst SD-WAN Manager formerly SD-WAN vManage contains an improper encoding or escaping of output vulnerability. This vulnerability could allow an authenticated, local attacker to execute arbitrary commands as root by supplying a crafted file to the affected system.”[1]
The CVE record adds: “A vulnerability in the CLI of Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, and Cisco Catalyst SD-WAN Validator, formerly SD-WAN vBond, could allow an authenticated, local attacker to execute arbitrary commands as root by supplying a crafted file to the affected system. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by uploading a crafted file to the affected system. A successful exploit could allow the attacker to perform command injection attacks on an affected system and elevate their privileges as the root user. To exploit this vulnerability, the attacker must have netadmin privileges on the affected system. This would require valid credentials or exploitation of or . Cisco is not aware of successful exploitation by…”[2]
The underlying weakness is CWE-116, in MITRE’s list of common software weaknesses.
It scores 7.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Cisco’s advisory has them[3]. CISA names the product as Cisco Catalyst SD-WAN Manager.
Most families won’t have Cisco Catalyst SD-WAN Manager; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 9 Jun 2026, 5 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 23 Jun 2026 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 25%. That’s in the top 3% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Cisco has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”[1]
- Check whether you use it.Cisco Catalyst SD-WAN Manager is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 23 Jun 2026 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 25%.[4] |
See also
Other Cisco Catalyst SD-WAN Manager flaws
- CVE-2026-76504: hex encoding ·
- CVE-2026-20262: directory or path traversal ·
- CVE-2026-20133: exposure of sensitive information to an unauthorized actor ·
- CVE-2026-20128: storing passwords in a recoverable format ·
Other Cisco flaws
- CVE-2026-76418, Cisco Secure Firewall ASA Software and Cisco Secure FTD Software: unchecked return value to NULL pointer dereference ·
- CVE-2026-76519, Cisco Secure Email Gateway: relative path traversal ·
- CVE-2026-76460, Cisco Identity Services Engine: incorrect use of privileged APIs ·
- CVE-2026-76461, Cisco Secure Email Gateway: SQL injection ·
- CVE-2026-20079, Cisco Secure Firewall Management Center (FMC) and Security Cloud Control (SCC) Firewall Management: firewall management center authentication bypass using an alternate path or channel ·
Similar flaws
- CVE-2024-38475, Apache HTTP Server: improper escaping of output ·
Added the same day
- CVE-2026-7473, Arista Extensible Operating System: incomplete comparison with missing factors ·
- CVE-2026-11645, Chrome and other Chromium browsers: out-of-bounds read and write ·
Every Cisco flaw on CISA’s list · Everything added in June 2026
References
- ^ Cybersecurity and Infrastructure Security Agency. “Cisco Catalyst SD-WAN Manager Improper Encoding or Escaping of Output Vulnerability”. Known Exploited Vulnerabilities Catalog, added 9 Jun 2026.
- ^ National Institute of Standards and Technology. “CVE-2026-20245 Detail”. National Vulnerability Database, published 4 Jun 2026.
- ^ Cisco. Advisories and fixes: sec.cloudapps.cisco.com, sec.cloudapps.cisco.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.253, percentile 97.9, 31 Oct 2026.
- CVE Program. “CVE-2026-20245”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.