CVE-2026-53225sctp: fix uninit-value in __sctp_rcv_asconf_lookup()

Official description

In the Linux kernel, the following vulnerability has been resolved: sctp: fix uninit-value in __sctp_rcv_asconf_lookup() __sctp_rcv_asconf_lookup() in net/sctp/input.c only checks that the ASCONF chunk can hold the ADDIP header and a parameter header, then calls af->from_addr_param(), which reads the full address (16 bytes for IPv6) trusting the parameter's declared length. An unauthenticated peer can send a truncated trailing ASCONF chunk that declares an IPv6 address parameter but stops after the 4-byte parameter header; reached from the no-association lookup path, from_addr_param() then reads uninitialized bytes past the parameter. Impact: an unauthenticated SCTP peer makes the receive path read up to 16 bytes of uninitialized memory past a truncated ASCONF address parameter. The sibling __sctp_rcv_init_lookup() bounds parameters with sctp_walk_params(); this path open-codes the fetch and omits the bound. Verify the whole address parameter lies within the chunk before from_addr_param() reads it, the same class of fix as commit 51e5ad549c43 ("net: sctp: fix KMSAN uninit-value in sctp_inq_pop").

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/446e0ecd845abc394b24ae2030a883572bec9d16
• https://git.kernel.org/stable/c/928dd94db23e8ba340f83d68f7f24d831b7a4426
• https://git.kernel.org/stable/c/d796cfd06074b579d265b28401306cadd30db945
• https://git.kernel.org/stable/c/8ce96f1182644079249a24ac7e2ffc32e0301a46
• https://git.kernel.org/stable/c/d6bd0bb7697ea8c0387b0d9d973453f479017b23
• https://git.kernel.org/stable/c/f76a8b323e28e0951f979dbef20a7496383c47df
• https://git.kernel.org/stable/c/8e86817b8af4d552f3c6fe04ca52bb0c8c57411d
• https://git.kernel.org/stable/c/f8373d7090b745728de66308deeecc67e8d319ce
• https://cert-portal.siemens.com/productcert/html/ssa-784472.html