Cisco customers encounter another SD-WAN zero-day under attack

Cisco customers are confronting yet another actively exploited zero-day vulnerability affecting the vendor’s SD-WAN management software, reinforcing pressure on organizations that have experienced rare breaks from active threats this year.

The vulnerability — CVE-2026-20245 — marks the seventh actively exploited zero-day in Cisco SD-WANs this year.

Cisco said it first became aware of active exploitation of the latest defect in the network management software earlier this month. The company disclosed the vulnerability, which was first spotted by Mandiant, on Thursday and warned that a security patch is not yet available and there are no workarounds to mitigate the defect in the meantime.

“A patch for this vulnerability will be provided on a future date,” a company spokesperson said in a statement. 

Cisco did not attribute the attacks to any specific group, describe the objectives of those attacks or share how many organizations have already been impacted.

The validation error defect affecting the Cisco Catalyst SD-WAN Manager allows authenticated or local attackers to execute commands as root, resulting in command-injection attacks on an affected system, the company said.

Yet, the scope of potential impact may be limited because exploitation requires valid credentials or privileged access through other means. Cisco said exploitation of a pair of zero-days it disclosed earlier this year —  CVE-2026-20182 or CVE-2026-20127 — could allow attackers the access required to exploit the new vulnerability. 

The company said it is “not aware of successful exploitation by other means,” adding that it “observed limited cases where the exploitation of this bug resulted in a configuration change pushed to edge devices.”

Landon Rice, senior exploit developer at VulnCheck, said the need for existing privileges “makes an attacker heavily reliant on previous vulnerabilities, or a net-new initial access vector, in order to be able to reach the privilege escalation path.”

Cisco advised customers to upgrade to fixed software released in May as part of its response to CVE-2026-20182 as a protective measure. 

Absent a patch that would provide organizations more protection against the new vulnerability, Cisco provided some indicators of compromise but noted that those same log entries may occur during standard operations. The company encouraged customers that need help distinguishing between legitimate and malicious activity to contact Cisco Technical Assistance Centers.

Cisco isn’t the only security vendor facing an onslaught of attacks on its customers, but it is among the most heavily targeted. The Cybersecurity and Infrastructure Security Agency has added seven vulnerabilities affecting Cisco SD-WANs and firewalls to its known exploited vulnerabilities catalog this year, not including CVE-2026-20245, which has yet to be added to the catalog.