{"id":"CVE-2026-98123","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration\n\nsctp_verify_asconf() walks ASCONF-ACK parameters with\nsctp_walk_params(), which advances by SCTP_PAD…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration\n\nsctp_verify_asconf() walks ASCONF-ACK parameters with\nsctp_walk_params(), which advances by SCTP_PAD…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < abf59d7f6fff23227256e8199aca5ade45758f8b","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3be02999ab9131a4b96eb1eda4ca48b1cea80f03","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7ba84e2971d208a2d6413a334ec28a8a32cdce0f","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2cb0b0b1ed69430bf73740377ea0a1c44c50db63","Linux 2.6.12"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T11:17:43.600","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98123","references":[{"url":"https://git.kernel.org/stable/c/2cb0b0b1ed69430bf73740377ea0a1c44c50db63","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3be02999ab9131a4b96eb1eda4ca48b1cea80f03","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7ba84e2971d208a2d6413a334ec28a8a32cdce0f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/abf59d7f6fff23227256e8199aca5ade45758f8b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T11:06:38.821Z","slug":"CVE-2026-98123","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nsctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration\n\nsctp_verify_asconf() walks ASCONF-ACK parameters with\nsctp_walk_params(), which advances by SCTP_PAD4(length), while the\nconsumer sctp_get_asconf_response() iterates the same parameters\nadvancing by the raw length, without padding. A single odd-length\nparameter desynchronises the two walks and makes the consumer\ninterpret attacker-controlled bytes at a misaligned offset.\n\nWhen those bytes yield a length of zero, the while loop over\nasconf_ack_len makes no progress, spinning forever in softirq\ncontext, and the watchdog reports a soft lockup. All reads stay\nwithin the received skb, so the lockup is a pure remote denial of\nservice. A remote peer can trigger it with a crafted ASCONF-ACK on\nan ADD-IP enabled association with an outstanding ASCONF (RFC 5061\nsection 4.1.2 requires the chunk to be authenticated, but the\npredefined empty key id 0 allows the peer to compute the same\nassociation HMAC from publicly exchanged parameters, so the gate\ndoes not help).\n\nThe SCTP_PARAM_ERR_CAUSE case of sctp_verify_asconf() also performs\nno length check, letting a parameter without a complete error\nheader reach the consumer, which reads errhdr.cause past the end of\nthe parameter, an out-of-bounds read.\n\nReject SCTP_PARAM_ERR_CAUSE parameters shorter than\nsizeof(struct sctp_addip_param) + sizeof(struct sctp_errhdr) at the\nverifier, and advance the consumer iterator with the same padding\nrule as the verifier to keep the two walks in lockstep. The verifier\nchange guarantees a complete error header in every ERR_CAUSE\nparameter the consumer can see, so the consumer's asconf_ack_len\ncheck is dropped and it returns err_param->cause directly. The\nconsumer padding fix is still required because odd lengths remain\nvalid for SCTP_PARAM_ERR_CAUSE per RFC 5061.\n\nThe issue was found by ZeroHive, a vulnerability hunting agent at\nTencent Yunding Lab.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}