Security advisory

{
  "id": "c8adadeccdccda253cc064f95e5b05c44fdf3c10807c3a5f52716b4d09751677",
  "url": "https://osv.dev/vulnerability/CVE-2018-15836",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2018-15836",
    "summary": "In verify_signed_hash() in lib/liboswkeys/signatures.c in Openswan before 2.6.50.1, the RSA implementation does not verify the value of padding string during PKCS#1 v1.5 signature verification. Consequently, a remote attacker can forge signatures when small public exponents are being used. IKEv2 signature verification is affected when RAW RSA keys are used.",
    "evidence": "osv:CVE-2018-15836",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2018-15836",
      "aliases": [
        "CVE-2018-15836"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/xelerance/openswan",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0b460be9e287fd335c8ce58129c67bf06065ef51"
                },
                {
                  "fixed": "9eaa6c2a823c1d2b58913506a15f9474bf857a3d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:xelerance:openswan:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.6.50.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "0b460be9e287fd335c8ce58129c67bf06065ef51"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "9eaa6c2a823c1d2b58913506a15f9474bf857a3d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.6.50",
            "v2.6.49",
            "v2.6.48",
            "v2.6.47.1",
            "v2.6.47",
            "v2.6.46",
            "v2.6.45",
            "v2.6.43",
            "v2.6.44",
            "v2.6.42",
            "v2.6.40",
            "v2.6.38",
            "v2.6.32",
            "v2.6.37",
            "v2.6.36",
            "v2.6.34",
            "v2.6.29",
            "v2.6.26",
            "v2.6.24",
            "v2.6.23",
            "v2.6.21",
            "v2.6.20",
            "v2.6.19",
            "v2.6.18",
            "v2.6.16",
            "v2.6.15",
            "v2.6.14",
            "v2.6.07",
            "v2.6.03",
            "v2.6.01",
            "v2.5.03",
            "v2.5.01"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-15836.json",
            "vanir_signatures": [
              {
                "id": "CVE-2018-15836-1ac51d67",
                "digest": {
                  "length": 900,
                  "function_hash": "236529740792023782679289609660264815960"
                },
                "source": "https://github.com/xelerance/openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3d",
                "target": {
                  "file": "lib/liboswkeys/signatures.c",
                  "function": "verify_signed_hash"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2018-15836-2d94594d",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "257282234818150788343041657178393295120",
                    "142560450995371773859260608519618091601",
                    "96950459911695153985521605877857233650",
                    "81033830470151624835191227279492282264"
                  ]
                },
                "source": "https://github.com/xelerance/openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3d",
                "target": {
                  "file": "lib/liboswkeys/signatures.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T13:29:33Z"
          }
        }
      ],
      "modified": "2026-10-20T13:29:33.397729015Z",
      "provider": "osv",
      "references": [
        "https://lists.openswan.org/pipermail/users/2018-August/023761.html",
        "https://github.com/xelerance/Openswan/commit/0b460be9e287fd335c8ce58129c67bf06065ef51",
        "https://github.com/xelerance/Openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3d"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2018-15836",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 387750,
  "published_at": "2018-09-26T21:29:00.913+00:00"
}