IKEv2 pre-authentication Null Pointer Dereference in EAP code

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-77206",
    "assignerOrgId": "d42dc95b-23f1-4e06-9076-20753a0fb0df",
    "assignerShortName": "libreswan",
    "dateUpdated": "2026-10-13T21:28:11.498Z",
    "dateReserved": "2026-08-20T18:13:09.377Z",
    "datePublished": "2026-10-13T21:28:11.498Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "d42dc95b-23f1-4e06-9076-20753a0fb0df",
        "shortName": "libreswan",
        "dateUpdated": "2026-10-13T21:28:11.498Z"
      },
      "title": "IKEv2 pre-authentication Null Pointer Dereference in EAP code",
      "descriptions": [
        {
          "lang": "en",
          "value": "Libreswan's IKEv2 state machine has a null pointer dereference bug in the EAP handling code for authentication. As a result of inconsistency within the IKEv2 state machine code, this bug can be triggered by any IKEv2 connection, even if EAP is not configured at all. The error is caused by a fall-through where it incorrectly dereferences ike->sa.st_eap which is NULL. A malicious IKE_AUTH packet can trigger this bug, meaning the peer does not need to be authenticated. The bug results in a crash and restart of the pluto daemon. No remote code execution is possible. Continued exploitation can cause a denial of service."
        }
      ],
      "affected": [
        {
          "vendor": "The Libreswan Project",
          "product": "libreswan",
          "collectionURL": "https://github.com/libreswan/libreswan",
          "packageName": "libreswan",
          "repo": "https://github.com/libreswan/libreswan",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "4.7",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "5.3.2"
            },
            {
              "version": "5.4",
              "status": "affected",
              "versionType": "semver",
              "lessThanOrEqual": "5.4"
            },
            {
              "version": "5.3.3",
              "status": "unaffected",
              "versionType": "semver"
            },
            {
              "version": "5.4.1",
              "status": "unaffected",
              "versionType": "semver"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "CWE-476: Null Pointer Dereference",
              "cweId": "CWE-476",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://libreswan.org/security/CVE-2026-77206/CVE-2026-77206.txt",
          "name": "Libreswan Security Advisory CVE-2026-77206",
          "tags": [
            "vendor-advisory"
          ]
        },
        {
          "url": "https://libreswan.org/security/CVE-2026-77206/",
          "name": "Libreswan CVE-2026-77206 Patches",
          "tags": [
            "patch"
          ]
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "Denial of service via null pointer dereference in EAP handling code when processing malicious IKE_AUTH packets"
            }
          ]
        }
      ],
      "metrics": [
        {
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ],
          "cvssV3_1": {
            "version": "3.1",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "attackVector": "NETWORK",
            "attackComplexity": "LOW",
            "privilegesRequired": "NONE",
            "userInteraction": "NONE",
            "scope": "UNCHANGED",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH"
          }
        },
        {}
      ],
      "configurations": [
        {
          "lang": "en",
          "value": "Any server or client that accepts IKEv2 connections is vulnerable. The bug can be triggered even if EAP is not configured at all."
        }
      ],
      "workarounds": [
        {
          "lang": "en",
          "value": "Apply the available patch or upgrade to a supported version. No configuration-based workaround is available."
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to libreswan 5.3.3 or 5.4.1 or later. Note that EAP was not functional in libreswan 5.3. If you need EAP support, use 5.4.1 or later. Patches are available at https://libreswan.org/security/CVE-2026-77206/"
        }
      ],
      "exploits": [
        {
          "lang": "en",
          "value": "No known exploitation in the wild. Exploitation requires sending a malicious IKE_AUTH packet and does not require peer authentication."
        }
      ],
      "timeline": [
        {
          "time": "2026-08-05T00:00:00.000Z",
          "lang": "en",
          "value": "Libreswan was notified of the issue via security@libreswan.org"
        },
        {
          "time": "2026-09-24T00:00:00.000Z",
          "lang": "en",
          "value": "Advanced notice given to supported customers and distributions"
        },
        {
          "time": "2026-10-05T00:00:00.000Z",
          "lang": "en",
          "value": "Public announcement and release of libreswan 5.3.3 and 5.4.1"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Claude (Anthropic)",
          "type": "tool"
        },
        {
          "lang": "en",
          "value": "David Korczynski (ADA Logics Ltd)",
          "type": "reporter"
        }
      ],
      "taxonomyMappings": [
        {
          "taxonomyName": "ATT&CK",
          "taxonomyVersion": "15.1",
          "taxonomyRelations": [
            {
              "taxonomyId": "T1499.004",
              "relationshipName": "maps to",
              "relationshipValue": "Application or System Exploitation (DoS)"
            }
          ]
        }
      ]
    }
  }
}