Skip to content
Heist/ feed
Back to feed
MediumFix available

curl — security advisory

Type: advisorySources: OSVAdvisory ID: ALPINE-CVE-2026-5545

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host. 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 request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials. An application that first uses Negotiate authentication to a server with `user1:password1` and then does another operation to the same server asking for any authentication method but for `user2:password2` (while the previous connection is still alive) - the second request gets confused and wrongly reuses the same connection and sends the new request over that connection thinking it uses a mix of user1's and user2's credentials when it is in fact still using the connection authenticated for user1...

Products
curl
Affected versions
Not specified
Fixed versions
8.14.1-r3, 8.20.0-r0
CVEs
CVE-2026-5545
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 06:41 UTC · Revision 1

Source evidence

ALPINE-CVE-2026-5545

core-osv · Original source

Published 13 May 2026, 13:01 UTC

libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host. 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 request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials. An application that first uses Negotiate authentication to a server with `user1:password1` and then does another operation to the same server asking for any authentication method but for `user2:password2` (while the previous connection is still alive) - the second request gets confused and wrongly reuses the same connection and sends the new request over that connection thinking it uses a mix of user1's and user2's credentials when it is in fact still using the connection authenticated for user1...

osv:ALPINE-CVE-2026-5545

curl

Fixed versions: 8.14.1-r3

curl

Fixed versions: 8.14.1-r3

curl

Fixed versions: 8.20.0-r0

curl

Fixed versions: 8.20.0-r0

Complete source record
{
  "id": "38917e98c87a4409de66c135687024f81260ea033fa8b29e63314ce2b842bb46",
  "url": "https://osv.dev/vulnerability/ALPINE-CVE-2026-5545",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ALPINE-CVE-2026-5545",
    "summary": "libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host. 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 request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials. An application that first uses Negotiate authentication to a server with `user1:password1` and then does another operation to the same server asking for any authentication method but for `user2:password2` (while the previous connection is still alive) - the second request gets confused and wrongly reuses the same connection and sends the new request over that connection thinking it uses a mix of user1's and user2's credentials when it is in fact still using the connection authenticated for user1...",
    "evidence": "osv:ALPINE-CVE-2026-5545",
    "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-r3",
            "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": "medium",
    "structured": {
      "id": "ALPINE-CVE-2026-5545",
      "aliases": [
        "ALPINE-CVE-2026-5545"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.10.6"
                },
                {
                  "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-2026-5545.json"
          },
          "ecosystem_specific": {}
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.10.6"
                },
                {
                  "fixed": "8.14.1-r3"
                }
              ]
            }
          ],
          "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-2026-5545.json"
          },
          "ecosystem_specific": {}
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.10.6"
                },
                {
                  "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-2026-5545.json"
          },
          "ecosystem_specific": {}
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "7.10.6"
                },
                {
                  "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-2026-5545.json"
          },
          "ecosystem_specific": {}
        }
      ],
      "modified": "2026-10-18T12:30:04.112589967Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-5545"
      ],
      "references": [
        "https://security.alpinelinux.org/vuln/CVE-2026-5545"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-5545",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 370046,
  "published_at": "2026-05-13T13:01:56.19+00:00"
}