Cisco Patches Another SD-WAN Zero-Day, the Sixth Exploited in 2026

Summary

Cisco released patches for CVE-2026-20182, a critical authentication bypass in Cisco Catalyst SD-WAN Controller and Manager that allows remote admin access. The vulnerability has been actively exploited by sophisticated threat actor UAT-8616 in targeted attacks since May 2026. This is the sixth SD-WAN zero-day exploited in 2026, with CISA adding it to the KEV catalog requiring federal agencies to patch within three days.

Full text

Cisco on Thursday announced the availability of patches for yet another critical SD-WAN zero-day vulnerability that has been exploited in attacks. It is the sixth SD-WAN flaw whose exploitation came to light in 2026. The new SD-WAN zero-day is tracked as CVE-2026-20182, and it has been described by Cisco as an authentication bypass vulnerability that can allow a remote attacker to gain admin privileges on the targeted system via specially crafted packets. The vulnerability affects the peering authentication mechanism in Cisco Catalyst SD-WAN Controller (formerly SD-WAN vSmart) and Cisco Catalyst SD-WAN Manager (formerly SD-WAN vManage). Cisco said it became aware of active exploitation in May, and the company’s Talos threat intelligence and research group revealed that CVE-2026-20182 appears to have been exploited in limited attacks by a threat actor it tracks as UAT-8616. UAT-8616 has been described by Talos researchers as a highly sophisticated group, but its motivation and potential connections to a specific country or known group have not been revealed. The same threat actor previously exploited CVE-2026-20127 to gain unauthorized access to SD-WAN systems.Advertisement. Scroll to continue reading. “UAT-8616 attempted to add SSH keys, modify NETCONF configurations, and escalate to root privileges. Our findings indicate that the infrastructure used by UAT-8616 to carry out exploitation and post-compromise activities also overlaps with the Operational Relay Box (ORB) networks that Talos monitors closely,” Talos explained. Rapid7 has been credited for reporting CVE-2026-20182 to Cisco. The cybersecurity firm, which shared the technical details with the vendor on March 9, said it discovered the weakness during an analysis of CVE-2026-20127, noting that they are different flaws affecting the same component. Rapid7 disclosed details of the vulnerability on Thursday, and Cisco has made indicators of compromise (IoCs) available to help companies detect potential attacks. CISA has added CVE-2026-20182 to its KEV catalog, instructing federal agencies to address it within three days. The KEV list currently includes 15 Cisco SD-WAN vulnerabilities, five of which were discovered this year. In addition to CVE-2026-20182, the other flaws are tracked as CVE-2026-20128, CVE-2026-20122, CVE-2026-20133, and CVE-2026-20127. An older SD-WAN vulnerability, CVE-2022-20775, was also flagged as exploited in the wild this year, alongside CVE-2026-20127. Cisco Talos on Thursday described 10 activity clusters observed exploiting SD-WAN vulnerabilities to deliver cryptocurrency miners, credential stealers, backdoors, webshells, and other malware and hacking tools. Related: Recent Cisco Catalyst SD-WAN Vulnerability Now Widely Exploited Related: Researcher Drops YellowKey, GreenPlasma Windows Zero-Days Related: Microsoft, Palo Alto Networks Find Many Vulnerabilities by Using AI on Their Own Code Written By Eduard Kovacs Eduard Kovacs (@EduardKovacs) is senior managing editor at SecurityWeek. He worked as a high school IT teacher before starting a career in journalism in 2011. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering. Daily Briefing Newsletter Subscribe to the SecurityWeek Email Briefing for the latest cybersecurity threats, trends, and expert insights. More from Eduard Kovacs Drupal Patches Highly Critical Vulnerability Exposing Websites to HackingGoogle’s Surge in Chrome Vulnerability Discoveries Likely Driven by AIAnthropic Silently Patches Claude Code Sandbox BypassReal-World ICS Security Tales From the TrenchesDrupal to Patch Highly Critical Vulnerability at Risk of Quick ExploitationMicrosoft Disrupts Malware-Signing Service Run by ‘Fox Tempest’ Critical Vulnerability Exposes Industrial Robot Fleets to HackingMillions Impacted Across Several US Healthcare Data Breaches Latest News ‘Underminr’ Vulnerability Lets Attackers Hide Malicious Connections Behind Trusted DomainsDrupal Vulnerability in Hacker Crosshairs Shortly After DisclosureIn Other News: Industrial Router Exploitation, CISA KEV Nomination Form, Gas Station HackingCanadian Man Arrested for Operating Kimwolf Botnet‘First VPN’ Cybercrime Service Disrupted, Administrator ArrestedTrendAI Patches Apex One Zero-Day Exploited in the WildGrafana Says Codebase and Other Data Stolen via TanStack Supply Chain AttackCisco Patches Critical Vulnerability in Secure Workload Trending Daily Briefing NewsletterSubscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts. Virtual Event: Threat Detection and Incident Response Summit May 20, 2026 Delve into big-picture strategies to reduce attack surfaces, improve patch management, conduct post-incident forensics, and tools and tricks needed in a modern organization. Register Webinar: Third-Party Risk in Practice June 4, 2026 Organizations are investing heavily in third-party risk management, but breaches, delays, and blind spots continue to persist. Join this live webinar as we examine the gap between how organizations think their third-party risk programs are performing and what’s actually happening in practice. Register People on the MoveJoe Chen has become Chief Technology Officer at Trellix.Usercentrics has named Pawan Hegde as COO and Elena Ignatova as CPTO.SecureAuth has named Mark van Oppen as Chief Revenue Officer.More People On The MoveExpert Insights Caught Off Guard: Securing AI After It Hits Production As enterprises rush AI projects into production, security teams are increasingly being forced into reactive mode. (Joshua Goldfarb) Cyber Resilience is the New Business Continuity Plan The organizations best prepared to face disruption are those that align security, continuity and risk management around what the business cannot afford to lose. (Steve Durbin) Enhancing Data Center Security Without Sacrificing Performance For AI data centers, where the stakes are the highest and performance constraints are the tightest, security and performance are no longer a zero-sum game. (Nadir Izrael) Is the SOC Obsolete, and We Just Haven’t Admitted It Yet? Many AI-first enterprises have already embraced sovereign architectures for general AI initiatives; cybersecurity—and the SOC—should be next. (Danelle Au) The Mythos Moment: Enterprises Must Fight Agents with Agents Only with the right platform and an agentic, AI-driven defense, will enterprises be able to protect themselves in the agentic era. (Etay Maor) Flipboard Reddit Whatsapp Whatsapp Email

Indicators of Compromise

• cve — CVE-2026-20182
• cve — CVE-2026-20127
• cve — CVE-2026-20128
• cve — CVE-2026-20122
• cve — CVE-2026-20133
• cve — CVE-2022-20775

Entities