Vulnerability-Lookup

GHSA-8WM8-3499-X4V9

Vulnerability from github – Published: 2026-07-25 00:31 – Updated: 2026-07-25 00:31

Details

A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs violating RFC 9112, including leading whitespace, plus sign prefixes, and trailing invalid characters. When libsoup operates behind a strict frontend proxy, this parsing differential can be exploited to smuggle HTTP requests.

Severity

5.4 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-66338"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-24T23:16:52Z",
    "severity": "MODERATE"
  },
  "details": "A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs violating RFC 9112, including leading whitespace, plus sign prefixes, and trailing invalid characters. When libsoup operates behind a strict frontend proxy, this parsing differential can be exploited to smuggle HTTP requests.",
  "id": "GHSA-8wm8-3499-x4v9",
  "modified": "2026-07-25T00:31:48Z",
  "published": "2026-07-25T00:31:48Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66338"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-66338"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2506950"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-66338 (GCVE-0-2026-66338)

Vulnerability from cvelistv5 – Published: 2026-07-24 23:01 – Updated: 2026-07-24 23:01

Title

Libsoup: libsoup: http request smuggling via permissive chunk-size parsing in soup_body_input_stream_read_chunked()

Summary

Severity

5.4 (Medium)


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

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

redhat

References

2 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-66338	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2506950	issue-trackingx_refsource_REDHAT

Impacted products

5 products

Vendor	Product	Version
Red Hat	Red Hat Enterprise Linux 10	cpe:/o:redhat:enterprise_linux:10
Red Hat	Red Hat Enterprise Linux 6	cpe:/o:redhat:enterprise_linux:6
Red Hat	Red Hat Enterprise Linux 7	cpe:/o:redhat:enterprise_linux:7
Red Hat	Red Hat Enterprise Linux 8	cpe:/o:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	cpe:/o:redhat:enterprise_linux:9

Date Public

2026-06-05 00:00

Credits

Upstream acknowledges cavid as the original reporter.

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:10"
          ],
          "defaultStatus": "affected",
          "packageName": "libsoup3",
          "product": "Red Hat Enterprise Linux 10",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:6"
          ],
          "defaultStatus": "affected",
          "packageName": "libsoup",
          "product": "Red Hat Enterprise Linux 6",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:7"
          ],
          "defaultStatus": "affected",
          "packageName": "libsoup",
          "product": "Red Hat Enterprise Linux 7",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:8"
          ],
          "defaultStatus": "affected",
          "packageName": "libsoup",
          "product": "Red Hat Enterprise Linux 8",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:9"
          ],
          "defaultStatus": "affected",
          "packageName": "libsoup",
          "product": "Red Hat Enterprise Linux 9",
          "vendor": "Red Hat"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Upstream acknowledges cavid as the original reporter."
        }
      ],
      "datePublic": "2026-06-05T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "A flaw was found in libsoup. The chunked transfer encoding parser uses a permissive parsing function for chunk sizes that silently accepts inputs violating RFC 9112, including leading whitespace, plus sign prefixes, and trailing invalid characters. When libsoup operates behind a strict frontend proxy, this parsing differential can be exploited to smuggle HTTP requests."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "namespace": "https://access.redhat.com/security/updates/classification/",
              "value": "Low"
            },
            "type": "Red Hat severity rating"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-444",
              "description": "Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-24T23:01:20.503Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2026-66338"
        },
        {
          "name": "RHBZ#2506950",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2506950"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-06-05T15:03:56.000Z",
          "value": "Reported to Red Hat."
        },
        {
          "lang": "en",
          "time": "2026-06-05T00:00:00.000Z",
          "value": "Made public."
        }
      ],
      "title": "Libsoup: libsoup: http request smuggling via permissive chunk-size parsing in soup_body_input_stream_read_chunked()",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      },
      "x_redhatCweChain": "CWE-444: Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request/Response Smuggling\u0027)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2026-66338",
    "datePublished": "2026-07-24T23:01:20.503Z",
    "dateReserved": "2026-07-24T22:32:18.748Z",
    "dateUpdated": "2026-07-24T23:01:20.503Z",
    "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-8WM8-3499-X4V9

CVE-2026-66338 (GCVE-0-2026-66338)

Tags

Sightings

Nomenclature