Vulnerability-Lookup

GHSA-Q3G2-M552-3R9C

Vulnerability from github – Published: 2026-07-24 21:52 – Updated: 2026-07-24 21:52

Summary

swift-nio-http2: Missing CR/LF/NUL validation in header values

Details

Summary

SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend through NIOHTTP2's HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling or response splitting.

Impact

Two related gaps in inbound header validation, against any application using HTTP2ToHTTP1Codec (or HTTP2FramePayloadToHTTP1Codec) to front an HTTP/1.1 backend:

Regular header field values were only checked against a forbidden-name list (connection, transfer-encoding, proxy-connection, keep-alive, upgrade); the value itself was never inspected. An attacker-controlled regular header field value containing CR or LF passed validation and, once serialized as name: value CRLF by the codec, terminated the field early and injected extra header lines into the outbound HTTP/1.1 message.

Pseudo-header values (:path in particular) were only checked against CR, LF and NUL. A :path value containing SP serializes into the request-target of METHOD SP request-target SP HTTP-version CRLF, so a value like /a HTTP/1.1 produces GET /a HTTP/1.1 HTTP/1.1 — a parser-differential request line depending on whether a downstream reader takes the first or last SP-delimited token as the version.

Neither of these is reachable on a stock pipeline: NIOHTTP1's outbound validator (enableOutboundHeaderValidation, on by default) already rejects these characters on write. The exposure is pipelines that skip outbound validation, or any code that reads validated-looking HTTPRequestHead.headers and forwards the values on trusting that HTTP/2 already checked them.

Fix

Fixed in 48bfd90 and 45bdf67.

Mitigation

Upgrade to 1.45.0

Severity

5.3 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

6.3 (Medium)


                  
                    CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "SwiftURL",
        "name": "swift-nio-http2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.45.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-64785"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-113",
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-24T21:52:10Z",
    "nvd_published_at": "2026-07-23T20:17:21Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nSwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let\nCR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend\nthrough NIOHTTP2\u0027s HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling\nor response splitting.\n\n## Impact\n\nTwo related gaps in inbound header validation, against any application\nusing HTTP2ToHTTP1Codec (or HTTP2FramePayloadToHTTP1Codec) to front an\nHTTP/1.1 backend:\n\nRegular header field values were only checked against a forbidden-name\nlist (connection, transfer-encoding, proxy-connection, keep-alive,\nupgrade); the value itself was never inspected. An attacker-controlled\nregular header field value containing CR or LF passed validation and, once\nserialized as `name: value CRLF` by the codec, terminated the field early\nand injected extra header lines into the outbound HTTP/1.1 message.\n\nPseudo-header values (`:path` in particular) were only checked against\nCR, LF and NUL. A `:path` value containing SP serializes into the\nrequest-target of `METHOD SP request-target SP HTTP-version CRLF`, so a\nvalue like `/a HTTP/1.1` produces `GET /a HTTP/1.1 HTTP/1.1` \u2014 a\nparser-differential request line depending on whether a downstream reader\ntakes the first or last SP-delimited token as the version.\n\nNeither of these is reachable on a stock pipeline: NIOHTTP1\u0027s outbound\nvalidator (`enableOutboundHeaderValidation`, on by default) already rejects\nthese characters on write. The exposure is pipelines that skip outbound\nvalidation, or any code that reads validated-looking `HTTPRequestHead.headers`\nand forwards the values on trusting that HTTP/2 already checked them.\n\n## Fix\n\nFixed in 48bfd90 and 45bdf67.\n\n## Mitigation\n\nUpgrade to 1.45.0",
  "id": "GHSA-q3g2-m552-3r9c",
  "modified": "2026-07-24T21:52:10Z",
  "published": "2026-07-24T21:52:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/apple/swift-nio-http2/security/advisories/GHSA-q3g2-m552-3r9c"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64785"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apple/swift-nio-http2/commit/45bdf670248be5f16ec0340e125dca285536f0fb"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apple/swift-nio-http2/commit/48bfd9067d7d1d15c4789440127a0cf36222ea43"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/apple/swift-nio-http2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apple/swift-nio-http2/releases/tag/1.45.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "swift-nio-http2: Missing CR/LF/NUL validation in header values"
}

CVE-2026-64785 (GCVE-0-2026-64785)

Vulnerability from cvelistv5 – Published: 2026-07-23 18:50 – Updated: 2026-07-24 20:06

Summary

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

SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend through NIOHTTP2's HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling or response splitting.
CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

apple

References

1 reference

URL	Tags
https://github.com/apple/swift-nio-http2/security…

Impacted products

1 product

Vendor	Product	Version
Apple	swift-nio-http2	Affected: 0 , < 1.45.0 (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-64785",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-24T20:06:09.684879Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-444",
                "description": "CWE-444 Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-24T20:06:58.518Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "swift-nio-http2",
          "vendor": "Apple",
          "versions": [
            {
              "lessThan": "1.45.0",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend through NIOHTTP2\u0027s HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling or response splitting. This vulnerability is addressed in swift-nio-http2 version 1.45.0."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend through NIOHTTP2\u0027s HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling or response splitting.",
              "lang": "en"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-23T18:50:40.468Z",
        "orgId": "286789f9-fbc2-4510-9f9a-43facdede74c",
        "shortName": "apple"
      },
      "references": [
        {
          "url": "https://github.com/apple/swift-nio-http2/security/advisories/GHSA-q3g2-m552-3r9c"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "286789f9-fbc2-4510-9f9a-43facdede74c",
    "assignerShortName": "apple",
    "cveId": "CVE-2026-64785",
    "datePublished": "2026-07-23T18:50:40.468Z",
    "dateReserved": "2026-07-20T18:11:03.398Z",
    "dateUpdated": "2026-07-24T20:06:58.518Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

GHSA-Q3G2-M552-3R9C

Summary

Impact

Fix

Mitigation

CVE-2026-64785 (GCVE-0-2026-64785)

Tags

Sightings

Nomenclature