Vulnerability-Lookup

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

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

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

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            "cpe:/o:redhat:enterprise_linux:10"
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          "packageName": "libsoup3",
          "product": "Red Hat Enterprise Linux 10",
          "vendor": "Red Hat"
        },
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          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:6"
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          "packageName": "libsoup",
          "product": "Red Hat Enterprise Linux 6",
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          "cpes": [
            "cpe:/o:redhat:enterprise_linux:7"
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          "packageName": "libsoup",
          "product": "Red Hat Enterprise Linux 7",
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          "cpes": [
            "cpe:/o:redhat:enterprise_linux:8"
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          "packageName": "libsoup",
          "product": "Red Hat Enterprise Linux 8",
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          "cpes": [
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      "metrics": [
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      "problemTypes": [
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      "title": "Libsoup: libsoup: http request smuggling via permissive chunk-size parsing in soup_body_input_stream_read_chunked()",
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    "dateReserved": "2026-07-24T22:32:18.748Z",
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      "title": "libsoup: libsoup: HTTP Request Smuggling via permissive chunk-size parsing in soup_body_input_stream_read_chunked()",
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}

GHSA-8WM8-3499-X4V9

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

Details

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"
    }
  ]
}

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

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

GHSA-8WM8-3499-X4V9

Tags

Sightings

Nomenclature