CVE-2026-6733 (GCVE-0-2026-6733)

Vulnerability from cvelistv5 – Published: 2026-06-17 17:14 – Updated: 2026-06-17 18:30
VLAI
Title
undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse
Summary
Impact: Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests. This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse. Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0. Workarounds: Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.
Severity
3.7 (Low)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-367 - Time-of-check Time-of-use (TOCTOU) Race Condition
Assigner
References
Impacted products
Vendor Product Version
undici undici Affected: 0 , < 6.26.0 (semver)
Unaffected: 6.26.0 (semver)
Affected: 7.0.0 , < 7.28.0 (semver)
Unaffected: 7.28.0 (semver)
Affected: 8.0.0 , < 8.5.0 (semver)
Unaffected: 8.5.0 (semver)
Create a notification for this product.
Credits
mcollina UlisesGascon
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-6733",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-17T18:30:07.748616Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-17T18:30:26.429Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/undici",
          "product": "undici",
          "vendor": "undici",
          "versions": [
            {
              "lessThan": "6.26.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.26.0",
              "versionType": "semver"
            },
            {
              "lessThan": "7.28.0",
              "status": "affected",
              "version": "7.0.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.28.0",
              "versionType": "semver"
            },
            {
              "lessThan": "8.5.0",
              "status": "affected",
              "version": "8.0.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "8.5.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "mcollina"
        },
        {
          "lang": "en",
          "type": "remediation verifier",
          "value": "UlisesGascon"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Impact:\nUndici\u0027s HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.\n\nThis requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.\n\nPatches:\nUpgrade to undici v6.26.0, v7.28.0 or v8.5.0.\n\nWorkarounds:\nDisable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool."
            }
          ],
          "value": "Impact:\nUndici\u0027s HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.\n\nThis requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.\n\nPatches:\nUpgrade to undici v6.26.0, v7.28.0 or v8.5.0.\n\nWorkarounds:\nDisable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 3.7,
            "baseSeverity": "LOW",
            "vectorString": "CVSS:3.1/AV:N/AC:H/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-367",
              "description": "CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-17T17:14:50.991Z",
        "orgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "shortName": "openjs"
      },
      "references": [
        {
          "url": "https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52"
        },
        {
          "url": "https://hackerone.com/reports/3582376"
        },
        {
          "url": "https://cna.openjsf.org/security-advisories.html"
        }
      ],
      "title": "undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse",
      "x_generator": {
        "engine": "cve-kit 1.0.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
    "assignerShortName": "openjs",
    "cveId": "CVE-2026-6733",
    "datePublished": "2026-06-17T17:14:50.991Z",
    "dateReserved": "2026-04-20T22:44:32.835Z",
    "dateUpdated": "2026-06-17T18:30:26.429Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-6733",
      "date": "2026-07-11",
      "epss": "0.00228",
      "percentile": "0.13555"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-6733\",\"sourceIdentifier\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"published\":\"2026-06-17T18:18:05.473\",\"lastModified\":\"2026-06-27T23:46:06.553\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Impact:\\nUndici\u0027s HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.\\n\\nThis requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.\\n\\nPatches:\\nUpgrade to undici v6.26.0, v7.28.0 or v8.5.0.\\n\\nWorkarounds:\\nDisable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.\"}],\"affected\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"affectedData\":[{\"vendor\":\"undici\",\"product\":\"undici\",\"defaultStatus\":\"unaffected\",\"packageURL\":\"pkg:npm/undici\",\"versions\":[{\"version\":\"0\",\"lessThan\":\"6.26.0\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.26.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.0\",\"lessThan\":\"7.28.0\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"7.28.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"8.0.0\",\"lessThan\":\"8.5.0\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"8.5.0\",\"versionType\":\"semver\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N\",\"baseScore\":3.7,\"baseSeverity\":\"LOW\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":2.2,\"impactScore\":1.4}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-06-17T18:30:07.748616Z\",\"id\":\"CVE-2026-6733\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-367\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*\",\"versionEndExcluding\":\"6.27.0\",\"matchCriteriaId\":\"632BE4D6-A743-4F05-9B3F-FE6A7B3E58D2\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*\",\"versionStartIncluding\":\"7.0.0\",\"versionEndExcluding\":\"7.28.0\",\"matchCriteriaId\":\"0C34D757-BB16-4E28-95D8-7D3FAC851B69\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*\",\"versionStartIncluding\":\"8.0.0\",\"versionEndExcluding\":\"8.5.0\",\"matchCriteriaId\":\"37F3655C-C7AE-4B13-A5EB-6FE0A9566124\"}]}]}],\"references\":[{\"url\":\"https://cna.openjsf.org/security-advisories.html\",\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52\",\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"tags\":[\"Mitigation\",\"Vendor Advisory\"]},{\"url\":\"https://hackerone.com/reports/3582376\",\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"tags\":[\"Issue Tracking\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-07-06T19:38:23+00:00",
      "cve": "CVE-2026-6733",
      "id": "CVE-2026-6733",
      "initial_release_date": "2026-06-17T17:14:50.991000+00:00",
      "product_status:fixed": "152",
      "product_status:known_affected": "48",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "undici: Undici: Response queue poisoning on reused keep-alive sockets can lead to incorrect response delivery.",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6733.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"cna\": {\"providerMetadata\": {\"orgId\": \"ce714d77-add3-4f53-aff5-83d477b104bb\", \"shortName\": \"openjs\", \"dateUpdated\": \"2026-06-17T17:14:50.991Z\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"Impact:\\nUndici\u0027s HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.\\n\\nThis requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.\\n\\nPatches:\\nUpgrade to undici v6.26.0, v7.28.0 or v8.5.0.\\n\\nWorkarounds:\\nDisable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.\", \"supportingMedia\": [{\"type\": \"text/html\", \"base64\": false, \"value\": \"Impact:\\nUndici\u0027s HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.\\n\\nThis requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.\\n\\nPatches:\\nUpgrade to undici v6.26.0, v7.28.0 or v8.5.0.\\n\\nWorkarounds:\\nDisable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.\"}]}], \"affected\": [{\"vendor\": \"undici\", \"product\": \"undici\", \"defaultStatus\": \"unaffected\", \"versions\": [{\"versionType\": \"semver\", \"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"6.26.0\"}, {\"versionType\": \"semver\", \"status\": \"unaffected\", \"version\": \"6.26.0\"}, {\"versionType\": \"semver\", \"status\": \"affected\", \"version\": \"7.0.0\", \"lessThan\": \"7.28.0\"}, {\"versionType\": \"semver\", \"status\": \"unaffected\", \"version\": \"7.28.0\"}, {\"versionType\": \"semver\", \"status\": \"affected\", \"version\": \"8.0.0\", \"lessThan\": \"8.5.0\"}, {\"versionType\": \"semver\", \"status\": \"unaffected\", \"version\": \"8.5.0\"}], \"packageURL\": \"pkg:npm/undici\"}], \"references\": [{\"url\": \"https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52\"}, {\"url\": \"https://hackerone.com/reports/3582376\"}, {\"url\": \"https://cna.openjsf.org/security-advisories.html\"}], \"credits\": [{\"lang\": \"en\", \"type\": \"remediation developer\", \"value\": \"mcollina\"}, {\"lang\": \"en\", \"type\": \"remediation verifier\", \"value\": \"UlisesGascon\"}], \"title\": \"undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse\", \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N\", \"baseScore\": 3.7, \"baseSeverity\": \"LOW\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"problemTypes\": [{\"descriptions\": [{\"cweId\": \"CWE-367\", \"lang\": \"en\", \"description\": \"CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition\", \"type\": \"CWE\"}]}], \"x_generator\": {\"engine\": \"cve-kit 1.0.0\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-6733\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-06-17T18:30:07.748616Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-06-17T18:30:16.063Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-6733\", \"assignerOrgId\": \"ce714d77-add3-4f53-aff5-83d477b104bb\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"openjs\", \"dateReserved\": \"2026-04-20T22:44:32.835Z\", \"datePublished\": \"2026-06-17T17:14:50.991Z\", \"dateUpdated\": \"2026-06-17T18:30:26.429Z\"}",
      "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.