{"id":"CVE-2026-99128","published":"2026-10-28T11:17:32.570","lastModified":"2026-10-28T11:17:32.570","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: validate chunk length in the inqueue parser\n\nSCTP chunks always include a four-byte generic header, but\nsctp_inq_pop() currently accepts shorter declared lengths. A zero-length\nchunk leaves chunk_end at the current header.\n\nWhen ASCONF is covered by the association's SCTP-AUTH policy,\nsctp_assoc_bh_rcv() can continue before the state machine performs its\nnormal chunk-length check. sctp_inq_pop() then returns the same malformed\nchunk repeatedly and the receive softirq can lock up.\n\nA remote SCTP peer can trigger this after establishing an association on\na kernel built with CONFIG_IP_SCTP and configured with\nnet.sctp.addip_enable=1 and net.sctp.auth_enable=1. The reproducer did\nnot require application credentials, a shared SCTP AUTH key, or\nnet.sctp.addip_noauth_enable=1.\n\nOn commit f967455fb2a5 (\"seg6: reset IP6CB after IPv6 decapsulation\"),\none zero-length ASCONF caused repeated\nwatchdog soft-lockup reports in a two-vCPU KVM guest. All 3 pre-trigger\nhealth probes succeeded, while 36 of 37 post-trigger probes failed. With\nthis change, all 37 post-trigger probes succeeded and no equivalent\nsoft-lockup signature appeared.\n\nReject chunks shorter than the generic SCTP header at the shared inqueue\nparser boundary. Mark the packet for discard before either caller can\ncontinue processing it, while preserving the four-byte generic minimum.\nDeclared-length 1 through 4 controls and kernel-generated ASCONF traffic\nremained healthy. The patched sctp_hello selftest passed for IPv4 and\nIPv6.\n\nThe complete private reproducer and validation evidence are available\ndirectly to maintainers on request.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/40507f59f230dcf60ae13cb48d34f8c6e9f40659","tags":[]},{"url":"https://git.kernel.org/stable/c/6cfc1b90cb86f4aabc69fb8e30128e07e2cdfa3a","tags":[]},{"url":"https://git.kernel.org/stable/c/9ac57e4c62e93c287b36080e5da3645690549990","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}