CVE-2026-53246

In the Linux kernel, the following vulnerability has been resolved:

sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing

When a listening SCTP server processes a COOKIE_ECHO chunk, the cached

peer INIT chunk embedded after the cookie is parsed and its parameters

are later walked by sctp_process_init() using sctp_walk_params().

However, the chunk header length of this cached INIT chunk was not

validated against the remaining buffer in the COOKIE_ECHO payload. If

the length field is inflated, the parameter walk can run beyond the

actual received data, leading to out-of-bounds reads and potential

memory corruption during later parameter handling (e.g. STATE_COOKIE

processing and kmemdup() copies).

Add a bounds check in sctp_unpack_cookie() to ensure the cached INIT

chunk length does not exceed the available data in the COOKIE_ECHO

buffer before it is used.