CVE-2018-16994

CVE-2018-16994 describes a denial-of-service vulnerability affecting Phoenix Contact AXL F BK PN, AXL F BK ETH, and AXL F BK ETH XC devices, as well as Bosch Rexroth S20-ETH-BK and S20-PN-BK+ fieldbus couplers. An unauthenticated remote attacker can send a specially crafted request containing non-standard symbols, leading to a complete lock-up of the affected bus coupler. This vulnerability carries a CVSS v3.1 score of 7.5 (HIGH), indicating a significant impact on availability (A:H) with low attack complexity (AC:L) and requiring no authentication (PR:N) or user interaction (UI:N). The attack vector is network-based (AV:N). Currently, there is no evidence of active exploitation, and no public exploit code (Metasploit, Nuclei, ExploitDB) is available. The vulnerability has received minimal community discussion and media coverage, suggesting low public awareness.