CVE-2026-5078 (GCVE-0-2026-5078)

Vulnerability from cvelistv5 – Published: 2026-06-03 05:56 – Updated: 2026-06-03 13:19
VLAI
Title
morgan vulnerable to Log Forging via unneutralized control characters in :remote-user
Summary
Impact: The morgan logging middleware's :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user.
Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-117 - Improper Output Neutralization for Logs
Assigner
References
Impacted products
Vendor Product Version
morgan morgan Affected: 1.2.0 , ≤ 1.10.1 (semver)
Unaffected: 1.11.0 (semver)
Create a notification for this product.
Credits
Yuki Matsuhashi Ulises Gascón Jon Church
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-5078",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-03T13:16:59.663217Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-03T13:19:32.922Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/morgan",
          "product": "morgan",
          "vendor": "morgan",
          "versions": [
            {
              "lessThanOrEqual": "1.10.1",
              "status": "affected",
              "version": "1.2.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "1.11.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Yuki Matsuhashi"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Ulises Gasc\u00f3n"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Jon Church"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Impact: The morgan logging middleware\u0027s :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user."
            }
          ],
          "value": "Impact: The morgan logging middleware\u0027s :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-117",
              "description": "CWE-117: Improper Output Neutralization for Logs",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-03T05:56:49.512Z",
        "orgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "shortName": "openjs"
      },
      "references": [
        {
          "url": "https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m"
        },
        {
          "url": "https://cna.openjsf.org/security-advisories.html"
        }
      ],
      "title": "morgan vulnerable to Log Forging via unneutralized control characters in :remote-user",
      "x_generator": {
        "engine": "cve-kit 1.0.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
    "assignerShortName": "openjs",
    "cveId": "CVE-2026-5078",
    "datePublished": "2026-06-03T05:56:49.512Z",
    "dateReserved": "2026-03-28T17:42:51.328Z",
    "dateUpdated": "2026-06-03T13:19:32.922Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-5078",
      "date": "2026-06-04",
      "epss": "0.00031",
      "percentile": "0.09193"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-5078\",\"sourceIdentifier\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"published\":\"2026-06-03T08:16:19.743\",\"lastModified\":\"2026-06-04T19:24:21.557\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Impact: The morgan logging middleware\u0027s :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N\",\"baseScore\":5.3,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":1.4}]},\"weaknesses\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-117\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:morgan_project:morgan:*:*:*:*:*:node.js:*:*\",\"versionStartIncluding\":\"1.2.0\",\"versionEndExcluding\":\"1.11.0\",\"matchCriteriaId\":\"BB39C2E2-D0C6-4871-944A-08DBC91BC438\"}]}]}],\"references\":[{\"url\":\"https://cna.openjsf.org/security-advisories.html\",\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m\",\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"tags\":[\"Mitigation\",\"Vendor Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"cna\": {\"providerMetadata\": {\"orgId\": \"ce714d77-add3-4f53-aff5-83d477b104bb\", \"shortName\": \"openjs\", \"dateUpdated\": \"2026-06-03T05:56:49.512Z\"}, \"title\": \"morgan vulnerable to Log Forging via unneutralized control characters in :remote-user\", \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"cweId\": \"CWE-117\", \"description\": \"CWE-117: Improper Output Neutralization for Logs\", \"type\": \"CWE\"}]}], \"affected\": [{\"vendor\": \"morgan\", \"product\": \"morgan\", \"versions\": [{\"status\": \"affected\", \"version\": \"1.2.0\", \"lessThanOrEqual\": \"1.10.1\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"1.11.0\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\", \"packageURL\": \"pkg:npm/morgan\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Impact: The morgan logging middleware\u0027s :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user.\", \"supportingMedia\": [{\"type\": \"text/html\", \"base64\": false, \"value\": \"Impact: The morgan logging middleware\u0027s :remote-user token extracts the Basic auth username from the Authorization request header and writes it to the log stream without neutralizing control characters. An unauthenticated attacker can send a crafted Authorization Basic header containing CR or LF bytes to inject forged log lines, breaking the one-request-per-line structure of access logs and enabling log forgery against downstream log consumers. The built-in combined, common, default, and short formats are affected, as well as any custom format that references :remote-user. Affected versions: morgan 1.2.0 through 1.10.1. Patches: upgrade to morgan 1.11.0, which neutralizes control characters in the :remote-user token output. Workarounds: use a custom format string that does not include :remote-user.\"}]}], \"references\": [{\"url\": \"https://github.com/expressjs/morgan/security/advisories/GHSA-4vj7-5mj6-jm8m\"}, {\"url\": \"https://cna.openjsf.org/security-advisories.html\"}], \"metrics\": [{\"format\": \"CVSS\", \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}], \"cvssV3_1\": {\"version\": \"3.1\", \"attackVector\": \"NETWORK\", \"attackComplexity\": \"LOW\", \"privilegesRequired\": \"NONE\", \"userInteraction\": \"NONE\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"LOW\", \"availabilityImpact\": \"NONE\", \"baseSeverity\": \"MEDIUM\", \"baseScore\": 5.3, \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N\"}}], \"credits\": [{\"lang\": \"en\", \"value\": \"Yuki Matsuhashi\", \"type\": \"reporter\"}, {\"lang\": \"en\", \"value\": \"Ulises Gasc\\u00f3n\", \"type\": \"remediation developer\"}, {\"lang\": \"en\", \"value\": \"Jon Church\", \"type\": \"remediation developer\"}], \"x_generator\": {\"engine\": \"cve-kit 1.0.0\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-5078\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-06-03T13:16:59.663217Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-06-03T13:19:27.190Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-5078\", \"assignerOrgId\": \"ce714d77-add3-4f53-aff5-83d477b104bb\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"openjs\", \"dateReserved\": \"2026-03-28T17:42:51.328Z\", \"datePublished\": \"2026-06-03T05:56:49.512Z\", \"dateUpdated\": \"2026-06-03T13:19:32.922Z\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.