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curl — security advisory

Type: advisorySources: OSVAdvisory ID: ALPINE-CVE-2026-5773

libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different "share" than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. When this happens, the same credentials are used and the server name is the same.

Products
curl
Affected versions
Not specified
Fixed versions
8.14.1-r3, 8.14.1-r4, 8.20.0-r0
CVEs
CVE-2026-5773
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 06:41 UTC · Revision 1

Source evidence

ALPINE-CVE-2026-5773

core-osv · Original source

Published 13 May 2026, 13:01 UTC

libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different "share" than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. When this happens, the same credentials are used and the server name is the same.

osv:ALPINE-CVE-2026-5773

curl

Fixed versions: 8.14.1-r3

curl

Fixed versions: 8.14.1-r4

curl

Fixed versions: 8.20.0-r0

curl

Fixed versions: 8.20.0-r0

Complete source record
{
  "id": "e2b8a6cd53bd82b4e5568d659b914826e586c1f380bc8c3107709cdf06e0495c",
  "url": "https://osv.dev/vulnerability/ALPINE-CVE-2026-5773",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ALPINE-CVE-2026-5773",
    "summary": "libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different \"share\" than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. When this happens, the same credentials are used and the server name is the same.",
    "evidence": "osv:ALPINE-CVE-2026-5773",
    "products": [
      {
        "name": {
          "value": "curl",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "8.14.1-r3",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "curl",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "8.14.1-r4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "curl",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "8.20.0-r0",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "curl",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "8.20.0-r0",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "ALPINE-CVE-2026-5773",
      "aliases": [
        "ALPINE-CVE-2026-5773"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.40.0"
                },
                {
                  "fixed": "8.14.1-r3"
                }
              ]
            }
          ],
          "package": {
            "name": "curl",
            "purl": "pkg:apk/alpine/curl?arch=source",
            "ecosystem": "Alpine:v3.21"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-5773.json"
          },
          "ecosystem_specific": {}
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.40.0"
                },
                {
                  "fixed": "8.14.1-r4"
                }
              ]
            }
          ],
          "package": {
            "name": "curl",
            "purl": "pkg:apk/alpine/curl?arch=source",
            "ecosystem": "Alpine:v3.22"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-5773.json"
          },
          "ecosystem_specific": {}
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.40.0"
                },
                {
                  "fixed": "8.20.0-r0"
                }
              ]
            }
          ],
          "package": {
            "name": "curl",
            "purl": "pkg:apk/alpine/curl?arch=source",
            "ecosystem": "Alpine:v3.23"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-5773.json"
          },
          "ecosystem_specific": {}
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.40.0"
                },
                {
                  "fixed": "8.20.0-r0"
                }
              ]
            }
          ],
          "package": {
            "name": "curl",
            "purl": "pkg:apk/alpine/curl?arch=source",
            "ecosystem": "Alpine:v3.24"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2026-5773.json"
          },
          "ecosystem_specific": {}
        }
      ],
      "modified": "2026-10-18T12:30:02.955213455Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-5773"
      ],
      "references": [
        "https://security.alpinelinux.org/vuln/CVE-2026-5773"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-5773",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 370032,
  "published_at": "2026-05-13T13:01:56.307+00:00"
}