CVE-2026-39963 (GCVE-0-2026-39963)
Vulnerability from cvelistv5
Published
2026-04-14 23:31
Modified
2026-04-15 13:23
CWE
  • CWE-565 - Reliance on Cookies without Validation and Integrity Checking
Summary
Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2 and below, the serendipity_setCookie() function in include/functions_config.inc.php uses $_SERVER['HTTP_HOST'] without validation as the domain parameter of setcookie(). An attacker who can influence the Host header at login time, such as via MITM, reverse proxy misconfiguration, or load balancer manipulation, can force authentication cookies including session tokens and auto-login tokens to be scoped to an attacker-controlled domain. This enables session fixation, token leakage to attacker-controlled infrastructure, and privilege escalation if an admin logs in under a poisoned Host header. This issue has been fixed in version 2.6.0.
Impacted products
Vendor Product Version
s9y Serendipity Version: < 2.6.0
Create a notification for this product.
Show details on NVD website


{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-39963",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-15T13:23:44.552367Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-15T13:23:48.591Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gf"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "Serendipity",
          "vendor": "s9y",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.6.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2  and below, the serendipity_setCookie() function in include/functions_config.inc.php uses $_SERVER[\u0027HTTP_HOST\u0027] without validation as the domain parameter of setcookie(). An attacker who can influence the Host header at login time, such as via MITM, reverse proxy misconfiguration, or load balancer manipulation, can force authentication cookies including session tokens and auto-login tokens to be scoped to an attacker-controlled domain. This enables session fixation, token leakage to attacker-controlled infrastructure, and privilege escalation if an admin logs in under a poisoned Host header. This issue has been fixed in version 2.6.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-565",
              "description": "CWE-565: Reliance on Cookies without Validation and Integrity Checking",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-14T23:31:13.843Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gf",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gf"
        },
        {
          "name": "https://github.com/s9y/Serendipity/releases/tag/2.6.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/s9y/Serendipity/releases/tag/2.6.0"
        }
      ],
      "source": {
        "advisory": "GHSA-4m6c-649p-f6gf",
        "discovery": "UNKNOWN"
      },
      "title": "Serendipity: Host Header Injection enables authentication cookie scoping to an attacker-controlled domain"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-39963",
    "datePublished": "2026-04-14T23:31:13.843Z",
    "dateReserved": "2026-04-08T00:01:47.626Z",
    "dateUpdated": "2026-04-15T13:23:48.591Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-39963\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-04-15T13:23:44.552367Z\"}}}], \"references\": [{\"url\": \"https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gf\", \"tags\": [\"exploit\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-04-15T13:23:40.363Z\"}}], \"cna\": {\"title\": \"Serendipity: Host Header Injection enables authentication cookie scoping to an attacker-controlled domain\", \"source\": {\"advisory\": \"GHSA-4m6c-649p-f6gf\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"CHANGED\", \"version\": \"3.1\", \"baseScore\": 6.9, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N\", \"integrityImpact\": \"LOW\", \"userInteraction\": \"REQUIRED\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"s9y\", \"product\": \"Serendipity\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 2.6.0\"}]}], \"references\": [{\"url\": \"https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gf\", \"name\": \"https://github.com/s9y/Serendipity/security/advisories/GHSA-4m6c-649p-f6gf\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/s9y/Serendipity/releases/tag/2.6.0\", \"name\": \"https://github.com/s9y/Serendipity/releases/tag/2.6.0\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Serendipity is a PHP-powered weblog engine. In versions 2.6-beta2  and below, the serendipity_setCookie() function in include/functions_config.inc.php uses $_SERVER[\u0027HTTP_HOST\u0027] without validation as the domain parameter of setcookie(). An attacker who can influence the Host header at login time, such as via MITM, reverse proxy misconfiguration, or load balancer manipulation, can force authentication cookies including session tokens and auto-login tokens to be scoped to an attacker-controlled domain. This enables session fixation, token leakage to attacker-controlled infrastructure, and privilege escalation if an admin logs in under a poisoned Host header. This issue has been fixed in version 2.6.0.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-565\", \"description\": \"CWE-565: Reliance on Cookies without Validation and Integrity Checking\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-04-14T23:31:13.843Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-39963\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-15T13:23:48.591Z\", \"dateReserved\": \"2026-04-08T00:01:47.626Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-04-14T23:31:13.843Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.


Loading…

Loading…

Loading…

Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.


Loading…

Loading…