{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-1525", "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "state": "PUBLISHED", "assignerShortName": "openjs", "dateReserved": "2026-01-28T12:04:51.369Z", "datePublished": "2026-03-12T19:56:55.092Z", "dateUpdated": "2026-03-12T20:46:13.379Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "shortName": "openjs", "dateUpdated": "2026-03-12T19:56:55.092Z"}, "title": "undici is vulnerable to Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-444", "description": "CWE-444 Inconsistent interpretation of HTTP requests ('HTTP Request/Response smuggling')", "type": "CWE"}]}], "impacts": [{"capecId": "CAPEC-33", "descriptions": [{"lang": "en", "value": "CAPEC-33 HTTP Request Smuggling"}]}, {"capecId": "CAPEC-273", "descriptions": [{"lang": "en", "value": "CAPEC-273 HTTP Response Smuggling"}]}], "affected": [{"vendor": "undici", "product": "undici", "collectionURL": "https://github.com/nodejs/undici/", "packageName": "undici", "repo": "https://github.com/nodejs/undici/", "versions": [{"status": "affected", "version": "< 6.24.0; 7.0.0 < 7.24.0"}, {"status": "unaffected", "version": "6.24.0: 7.24.0"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "Undici allows duplicate HTTP\u00a0Content-Length\u00a0headers when they are provided in an array with case-variant names (e.g.,\u00a0Content-Length\u00a0and\u00a0content-length). This produces malformed HTTP/1.1 requests with multiple conflicting\u00a0Content-Length\u00a0values on the wire.\n\nWho is impacted:\n\n * Applications using\u00a0undici.request(),\u00a0undici.Client, or similar low-level APIs with headers passed as flat arrays\n * Applications that accept user-controlled header names without case-normalization\n\n\nPotential consequences:\n\n * Denial of Service: Strict HTTP parsers (proxies, servers) will reject requests with duplicate\u00a0Content-Length\u00a0headers (400 Bad Request)\n * HTTP Request Smuggling: In deployments where an intermediary and backend interpret duplicate headers inconsistently (e.g., one uses the first value, the other uses the last), this can enable request smuggling attacks leading to ACL bypass, cache poisoning, or credential hijacking", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Undici allows duplicate HTTP&nbsp;<code>Content-Length</code>&nbsp;headers when they are provided in an array with case-variant names (e.g.,&nbsp;<code>Content-Length</code>&nbsp;and&nbsp;<code>content-length</code>). 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This produces malformed HTTP/1.1 requests with multiple conflicting&nbsp;<code>Content-Length</code>&nbsp;values on the wire.</p><p><strong>Who is impacted:</strong></p><ul><li>Applications using&nbsp;<code>undici.request()</code>,&nbsp;<code>undici.Client</code>, or similar low-level APIs with headers passed as flat arrays</li><li>Applications that accept user-controlled header names without case-normalization</li></ul><p><strong>Potential consequences:</strong></p><ul><li><strong>Denial of Service</strong>: Strict HTTP parsers (proxies, servers) will reject requests with duplicate&nbsp;<code>Content-Length</code>&nbsp;headers (400 Bad Request)</li><li><strong>HTTP Request Smuggling</strong>: In deployments where an intermediary and backend interpret duplicate headers inconsistently (e.g., one uses the first value, the other uses the last), this can enable request smuggling attacks leading to ACL bypass, cache poisoning, or credential hijacking</li></ul>", "base64": false}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-444", "description": "CWE-444 Inconsistent interpretation of HTTP requests ('HTTP Request/Response smuggling')"}]}], "providerMetadata": {"orgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "shortName": "openjs", "dateUpdated": "2026-03-12T19:56:55.092Z"}}}, "cveMetadata": {"cveId": "CVE-2026-1525", "state": "PUBLISHED", "dateUpdated": "2026-03-12T20:46:13.379Z", "dateReserved": "2026-01-28T12:04:51.369Z", "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb", "datePublished": "2026-03-12T19:56:55.092Z", "assignerShortName": "openjs"}, "dataVersion": "5.2"}

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