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guzzle — security advisory

Type: advisorySources: OSVAdvisory ID: UBUNTU-CVE-2026-55568

Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, in certain configurations, traffic expected to be protected by TLS on the hop to the proxy is transmitted in cleartext. Proxy authentication credentials (the Proxy-Authorization header, proxy userinfo in the proxy URL, or CURLOPT_PROXYUSERPWD) are sent without encryption, and the CONNECT target host and port for tunneled HTTPS requests are exposed. The built-in cURL handlers (GuzzleHttp\Handler\CurlHandler and GuzzleHttp\Handler\CurlMultiHandler, used by default whenever the PHP cURL extension is available) accept an https:// proxy. libcurl older than 7.50.2 silently treats an https:// proxy as a plaintext http:// proxy. The TLS connection to the proxy is never established, and the proxy leg is cleartext with no error or warning. An application is affected when it sends requests through one of the built-in cURL handlers, configures an https:// proxy expecting the proxy connection itself to be encrypted, and runs with libcurl older than 7.50.2. This vulnerability is fixed in 7.12.1.

Products
guzzle
Affected versions
7.13.1-1, 7.15.1-1, 7.15.2-1, 7.15.3-1, 7.4.5-1, 7.9.2-0.1, 7.9.2-0.1build1
Fixed versions
Not specified
CVEs
CVE-2026-55568
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 02:46 UTC · Revision 1

Source evidence

UBUNTU-CVE-2026-55568

core-osv · Original source

Published 23 Jun 2026, 16:17 UTC

Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, in certain configurations, traffic expected to be protected by TLS on the hop to the proxy is transmitted in cleartext. Proxy authentication credentials (the Proxy-Authorization header, proxy userinfo in the proxy URL, or CURLOPT_PROXYUSERPWD) are sent without encryption, and the CONNECT target host and port for tunneled HTTPS requests are exposed. The built-in cURL handlers (GuzzleHttp\Handler\CurlHandler and GuzzleHttp\Handler\CurlMultiHandler, used by default whenever the PHP cURL extension is available) accept an https:// proxy. libcurl older than 7.50.2 silently treats an https:// proxy as a plaintext http:// proxy. The TLS connection to the proxy is never established, and the proxy leg is cleartext with no error or warning. An application is affected when it sends requests through one of the built-in cURL handlers, configures an https:// proxy expecting the proxy connection itself to be encrypted, and runs with libcurl older than 7.50.2. This vulnerability is fixed in 7.12.1.

osv:UBUNTU-CVE-2026-55568

guzzle

Fixed versions: Not specified

guzzle

Fixed versions: Not specified

guzzle

Fixed versions: Not specified

guzzle

Fixed versions: Not specified

Complete source record
{
  "id": "84c4bce5d9943536e2cabee5123a4fcda6494fc2f312919842ffb8261af10087",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-55568",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-CVE-2026-55568",
    "summary": "Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, in certain configurations, traffic expected to be protected by TLS on the hop to the proxy is transmitted in cleartext. Proxy authentication credentials (the Proxy-Authorization header, proxy userinfo in the proxy URL, or CURLOPT_PROXYUSERPWD) are sent without encryption, and the CONNECT target host and port for tunneled HTTPS requests are exposed. The built-in cURL handlers (GuzzleHttp\\Handler\\CurlHandler and GuzzleHttp\\Handler\\CurlMultiHandler, used by default whenever the PHP cURL extension is available) accept an https:// proxy. libcurl older than 7.50.2 silently treats an https:// proxy as a plaintext http:// proxy. The TLS connection to the proxy is never established, and the proxy leg is cleartext with no error or warning. An application is affected when it sends requests through one of the built-in cURL handlers, configures an https:// proxy expecting the proxy connection itself to be encrypted, and runs with libcurl older than 7.50.2. This vulnerability is fixed in 7.12.1.",
    "evidence": "osv:UBUNTU-CVE-2026-55568",
    "products": [
      {
        "name": {
          "value": "guzzle",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "7.4.5-1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "guzzle",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "7.9.2-0.1",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "guzzle",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "7.9.2-0.1build1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "7.13.1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "7.15.1-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "7.15.2-1",
            "evidence": "/affected/2/versions"
          },
          {
            "value": "7.15.3-1",
            "evidence": "/affected/2/versions"
          }
        ]
      },
      {
        "name": {
          "value": "guzzle",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "7.9.2-0.1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "7.9.2-0.1build1",
            "evidence": "/affected/3/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "UBUNTU-CVE-2026-55568",
      "aliases": [
        "UBUNTU-CVE-2026-55568"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "guzzle",
            "purl": "pkg:deb/ubuntu/guzzle?arch=source&distro=noble",
            "ecosystem": "Ubuntu:24.04:LTS"
          },
          "versions": [
            "7.4.5-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55568.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "php-guzzlehttp-guzzle",
                "binary_version": "7.4.5-1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "guzzle",
            "purl": "pkg:deb/ubuntu/guzzle?arch=source&distro=questing",
            "ecosystem": "Ubuntu:25.10"
          },
          "versions": [
            "7.9.2-0.1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55568.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "php-guzzlehttp-guzzle",
                "binary_version": "7.9.2-0.1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "guzzle",
            "purl": "pkg:deb/ubuntu/guzzle?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "7.9.2-0.1build1",
            "7.13.1-1",
            "7.15.1-1",
            "7.15.2-1",
            "7.15.3-1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55568.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "php-guzzlehttp-guzzle",
                "binary_version": "7.15.3-1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "guzzle",
            "purl": "pkg:deb/ubuntu/guzzle?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "7.9.2-0.1",
            "7.9.2-0.1build1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55568.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "php-guzzlehttp-guzzle",
                "binary_version": "7.9.2-0.1build1"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T12:59:07.518794997Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-55568"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-55568",
        "https://www.cve.org/CVERecord?id=CVE-2026-55568",
        "https://github.com/guzzle/guzzle/security/advisories/GHSA-wpwq-4j6v-78m3"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-55568",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 359322,
  "published_at": "2026-06-23T16:17:00+00:00"
}