CVE-2026-18746 NULL pointer dereference in Zephyr LwM2M client when the CoAP Block1 context pool is exhausted

parsewriteop in subsys/net/lib/lwm2m/lwm2mmessagehandling.c handles inbound CoAP WRITE/CREATE requests that carry a Block1 option. For the first block of a transfer it called initblockctx and then immediately stored the peer-selected block size with blockctx-ctx.blocksize = blocksize before...

CVE-2026-18746

The Zephyr LwM2M client is vulnerable to a NULL pointer dereference in the parse_write_op() function within subsys/net/lib/lwm2m/lwm2m_message_handling.c. When the static CoAP Block1 context pool (defaulting to 3 entries) is exhausted, the init_block_ctx() function returns -ENOMEM and sets the ca...

CVE-2026-18746 NULL pointer dereference in Zephyr LwM2M client when the CoAP Block1 context pool is exhausted

parsewriteop in subsys/net/lib/lwm2m/lwm2mmessagehandling.c handles inbound CoAP WRITE/CREATE requests that carry a Block1 option. For the first block of a transfer it called initblockctx and then immediately stored the peer-selected block size with blockctx-ctx.blocksize = blocksize before...

PT-2026-102412

Name of the Vulnerable Software and Affected Versions Zephyr LwM2M client affected versions not specified Description The parse write op function in subsys/net/lib/lwm2m/lwm2m message handling.c contains a NULL pointer dereference when handling inbound CoAP WRITE/CREATE requests with a Block1...