CVE-2026-23438 net: mvpp2: guard flow control update with global_tx_fc in buffer switching

In the Linux kernel, the following vulnerability has been resolved: net: mvpp2: guard flow control update with globaltxfc in buffer switching mvpp2bmswitchbuffers unconditionally calls mvpp2bmpoolupdateprivfc when switching between per-cpu and shared buffer pool modes. This function programs CM3...

CVE-2026-23438

In the Linux kernel mvpp2 driver, CVE-2026-23438 arises from an unconditional access to CM3 flow control via mvpp2_cm3_read()/mvpp2_cm3_write() in mvpp2_bm_switch_buffers(), when priv->cm3_base is NULL (e.g., CM3 SRAM not present in device tree). This can crash the kernel on MTU changes that c...