Mobile tactical networks (MTNs) require agile operation, robustness, strong security protection, and high efficiency in order to fulfill their missions in contested environments. Research has shown that the classical layered protocol architecture has limitations and many cross-layer security techniques have been proposed in order to address these requirements. Most cross-layer techniques focus on a specific solution. A general framework is needed in order to support future diversified security applications. In this paper, we propose a cross-layer security management (CLSM) framework for MTNs, which provides a platform for developing various security services in MTNs. CLSM formalizes several functional blocks and control flows among these blocks, which include a local layer security-related attribute classification module, a security information retrieval engine, a security metric evaluation engine, a security knowledge repository, a shared security metric store, and a security related services module. We describe how CLSM can improve security performance in MTNs through two examples: intrusion detection and agile routing.