Amazon Threat Intelligence is warning of an active Interlock ransomware campaign that's exploiting a recently disclosed critical security flaw in Cisco Secure Firewall Management Center (FMC) Software.
The vulnerability in question is CVE-2026-20131 (CVSS score: 10.0), a case of insecure deserialization of user-supplied Java byte stream, which could allow an unauthenticated, remote attacker to
According to data gleaned from the tech giant's MadPot global sensor network , the security flaw is said to have been exploited as a zero-day since January 26, 2026, more than a month before it was publicly disclosed by Cisco.
"This wasn't just another vulnerability exploit; Interlock had a zero-day in their hands, giving them a week's head start to compromise organizations before defenders even knew to look.
Upon making this discovery, we shared our findings with Cisco to help support their investigation and protect customers," CJ Moses, chief information security officer (CISO) of Amazon Integrated Security, said in a report shared with The Hacker News.
The discovery, Amazon said, was made possible, thanks to an operational security blunder on the part of the threat actor that exposed their cybercrime group's operational toolkit via a misconfigured infrastructure server, offering insights into its multi-stage attack chain, bespoke remote access trojans, reconnaissance scripts, and evasion techniques.