{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"
            },
            {
              "fixed": "abf59d7f6fff23227256e8199aca5ade45758f8b"
            },
            {
              "fixed": "3be02999ab9131a4b96eb1eda4ca48b1cea80f03"
            },
            {
              "fixed": "7ba84e2971d208a2d6413a334ec28a8a32cdce0f"
            },
            {
              "fixed": "2cb0b0b1ed69430bf73740377ea0a1c44c50db63"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.12"
            },
            {
              "fixed": "6.12.111"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.53"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98123.json"
  },
  "details": "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_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-\u003ecause 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.",
  "id": "CVE-2026-98123",
  "modified": "2026-09-27T03:30:37.917366136Z",
  "published": "2026-09-25T10:36:05.993Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2cb0b0b1ed69430bf73740377ea0a1c44c50db63"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3be02999ab9131a4b96eb1eda4ca48b1cea80f03"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ba84e2971d208a2d6413a334ec28a8a32cdce0f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/abf59d7f6fff23227256e8199aca5ade45758f8b"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98123.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98123"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "sctp: fix soft lockup from unpadded ASCONF-ACK parameter iteration"
}