Auerswald COMfortel - Path Traversal (CVE-2021-40856)
204Exploiting IPs reported
Auerswald COMfortel 1400 IP and 2600 IP before 2.8G devices allow Authentication Bypass via the /about/../ substring.
CrowdSec analysis
CVE-2021-40856 is a vulnerability affecting Auerswald COMfortel IP devices, where improper path handling enables authentication bypass through certain crafted requests.
CrowdSec has been tracking this vulnerability and its exploits since 1st of June 2025.
According to CrowdSec data, while opportunistic exploitation dominates, a portion of threat actors trying to exploit CVE-2021-40856 apply basic targeting methods such as port or service detection. This indicates emerging patterns of selective targeting. In addition, according to the CrowdSec network, attack volume against CVE-2021-40856 has dipped slightly compared to the previous week. Although still commonly targeted, the decline suggests a cooling-off period. Long-term relevance remains, but attention is waning.
Observed exploitation attempts typically target URLs containing /about/.. combined with specific request patterns.
Exploitation
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Protection
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Blocklist
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