Security Affairs newsletter Round 539 by Pierluigi Paganini

On April 18th 2025, Microsoft announced Exchange Server Security Changes for Hybrid Deployments and accompanying non-security Hot Fix. Microsoft made these changes in the general interest of improving the security of hybrid Exchange deployments. Following further investigation, Microsoft identified specific security implications tied to the guidance and configuration steps outlined in the April announcement. Microsoft is issuing CVE-2025-53786 to document a vulnerability that is addressed by taking the steps documented with the April 18th announcement. Microsoft strongly recommends reading the information, installing the April 2025 (or later) Hot Fix and implementing the changes in your Exchange Server and hybrid environment.

CVE-2025-7775 is a memory overflow (CWE-119) in Citrix NetScaler ADC and NetScaler Gateway that can lead to remote code execution and/or denial of service. It is triggered when the appliance is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, or RDP Proxy) or AAA virtual server, or — on 13.1, 14.1, 13.1-FIPS, and NDcPP builds — when load-balancing virtual servers of type HTTP, SSL, or HTTP_QUIC are bound with IPv6 services or servicegroups with IPv6 servers (including DBS IPv6), or a CR virtual server of type HDX is in use. A remote, unauthenticated attacker (CVSS 4.0 network vector with no privileges required) who triggers the memory overflow can execute code with high impact on confidentiality and integrity or crash the device. Organizations running NetScaler in these exposed configurations, notably as remote-access gateways, are affected. Exploitation is confirmed in the wild: Citrix has confirmed active exploitation, the flaw was added to CISA's KEV catalog on 2025-08-26, and EPSS estimates a 19.6% probability of exploitation within 30 days (97th percentile).

Do: Upgrade all NetScaler ADC and Gateway appliances to the patched builds on the 13.1, 14.1, 13.1-FIPS, and NDcPP release trains identified in Citrix's security bulletin, prioritizing internet-facing devices. Audit configurations for Gateway (VPN/ICA Proxy/CVPN/RDP Proxy) or AAA virtual servers, HTTP/SSL/HTTP_QUIC LB virtual servers with IPv6 bindings, and CR virtual servers of type HDX to confirm exposure. The KEV listing makes applying vendor mitigations or the upgrade mandatory for US federal agencies under BOD 22-01.

A vulnerability was identified in Docker Desktop that allows local running Linux containers to access the Docker Engine API via the configured Docker subnet, at 192.168.65.7:2375 by default. This vulnerability occurs with or without Enhanced Container Isolation (ECI) enabled, and with or without the "Expose daemon on tcp://localhost:2375 without TLS" option enabled. This can lead to execution of a wide range of privileged commands to the engine API, including controlling other containers, creating new ones, managing images etc. In some circumstances (e.g. Docker Desktop for Windows with WSL backend) it also allows mounting the host drive with the same privileges as the user running Docker Desktop.