Where
AND
-Infinity
0
Severity
9.1
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L

subsys/net/lib/lwm2m/lwm2mpullcontext.c copied the firmware-update Package URI into a fixed static buffer (context.uri, size CONFIGLWM2MSWMGMTPACKAGEURILEN, default 128) with memcpy(context.uri, uri, LWM2MPACKAGEURILEN), copying exactly the destination size with no length validation. The Firmware-Update object stores the server-supplied Package URI (/5/0/1) in a 255-byte buffer, so a LwM2M management server (or an on-path attacker on a session lacking strong DTLS) can WRITE a URI of 128-254 characters; only the first 128 bytes are then copied into context.uri with no NUL terminator. That buffer is subsequently consumed as a C string by httpparserparseurl(context.uri, strlen(context.uri), ...), strlen-based CoAP URI-path/PROXY-URI option appends, and lwm2mparsepeerinfo(), causing an out-of-bounds read of adjacent static memory. The over-read bytes are appended to outbound CoAP requests (information disclosure of adjacent device memory to the server/proxy) and can crash the device (denial of service). The vulnerable copy was introduced by the pull-context refactor (first released in v3.0.0) and is present through v4.4.0; the default-on CONFIGLWM2MFIRMWAREUPDATEPULLSUPPORT path is affected. The fix adds a strlen(uri) >= sizeof(context.uri) check returning -ENOMEM and switches to strcpy(), guaranteeing a bounded, NUL-terminated buffer.

First published (updated )

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