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OESA-2026-2451 (CVE-2026-4873)

Vulnerability from osv_openeuler – Published: 2026-05-22 11:11 – Updated: 2026-08-06 11:11 – Source website
VLAI
Summary
curl security update
Details

cURL is a computer software project providing a library (libcurl) and command-line tool (curl) for transferring data using various protocols.

Security Fix(es):

A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead transmit data unencrypted.(CVE-2026-4873)

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...(CVE-2026-5545)

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.(CVE-2026-5773)

curl might erroneously pass on credentials for a first proxy to a second proxy.

This can happen when the following conditions are true:

  1. curl is setup to use specific different proxies for different URL schemes
  2. the first proxy needs credentials
  3. the second proxy uses no credentials
  4. while using the first proxy (using say http://), curl is asked to follow a redirect to a URL using another scheme (say https://), accessed using a second, different, proxy(CVE-2026-6253)

Using libcurl, when a custom Host: header is first set for an HTTP request and a second request is subsequently done using the same easy handle but without the custom Host: header set, the second request would use stale information and pass on cookies meant for the first host in the second request. Leak them.(CVE-2026-6276)

When asked to both use a .netrc file for credentials and to follow HTTP redirects, libcurl could leak the password used for the first host to the followed-to host under certain circumstances.(CVE-2026-6429)

Successfully using libcurl to do a transfer over a specific HTTP proxy (proxyA) with Digest authentication and then changing the proxy host to a second one (proxyB) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the Proxy-Authorization: header field meant for proxyA, to proxyB.(CVE-2026-7168)

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "aarch64": [
          "curl-7.79.1-49.oe2203sp4.aarch64.rpm",
          "curl-debuginfo-7.79.1-49.oe2203sp4.aarch64.rpm",
          "curl-debugsource-7.79.1-49.oe2203sp4.aarch64.rpm",
          "libcurl-7.79.1-49.oe2203sp4.aarch64.rpm",
          "libcurl-devel-7.79.1-49.oe2203sp4.aarch64.rpm"
        ],
        "noarch": [
          "curl-help-7.79.1-49.oe2203sp4.noarch.rpm"
        ],
        "src": [
          "curl-7.79.1-49.oe2203sp4.src.rpm"
        ],
        "x86_64": [
          "curl-7.79.1-49.oe2203sp4.x86_64.rpm",
          "curl-debuginfo-7.79.1-49.oe2203sp4.x86_64.rpm",
          "curl-debugsource-7.79.1-49.oe2203sp4.x86_64.rpm",
          "libcurl-7.79.1-49.oe2203sp4.x86_64.rpm",
          "libcurl-devel-7.79.1-49.oe2203sp4.x86_64.rpm"
        ]
      },
      "package": {
        "ecosystem": "openEuler:22.03-LTS-SP4",
        "name": "curl",
        "purl": "pkg:rpm/openEuler/curl\u0026distro=openEuler-22.03-LTS-SP4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.79.1-49.oe2203sp4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "severity": "High"
  },
  "details": "cURL is a computer software project providing a library (libcurl) and command-line tool (curl) for transferring data using various protocols.\r\n\r\nSecurity Fix(es):\n\nA vulnerability exists where a connection requiring TLS incorrectly reuses an\nexisting unencrypted connection from the same connection pool. If an initial\ntransfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request\nto that same host bypasses the TLS requirement and instead transmit data\nunencrypted.(CVE-2026-4873)\n\nlibcurl might in some circumstances reuse the wrong connection when asked to\ndo an authenticated HTTP(S) request after a Negotiate-authenticated one, when\nboth use the same host.\n\nlibcurl features a pool of recent connections so that subsequent requests can\nreuse an existing connection to avoid overhead.\n\nWhen reusing a connection a range of criteria must be met. Due to a logical\nerror in the code, a request that was issued by an application could\nwrongfully reuse an existing connection to the same server that was\nauthenticated using different credentials.\n\nAn application that first uses Negotiate authentication to a server with\n`user1:password1` and then does another operation to the same server asking\nfor any authentication method but for `user2:password2` (while the previous\nconnection is still alive) - the second request gets confused and wrongly\nreuses the same connection and sends the new request over that connection\nthinking it uses a mix of user1\u0026apos;s and user2\u0026apos;s credentials when it is in fact\nstill using the connection authenticated for user1...(CVE-2026-5545)\n\nlibcurl might in some circumstances reuse the wrong connection for SMB(S)\ntransfers.\n\nlibcurl features a pool of recent connections so that subsequent requests can\nreuse an existing connection to avoid overhead.\n\nWhen reusing a connection a range of criteria must be met. Due to a logical\nerror in the code, a network transfer operation that was requested by an\napplication could wrongfully reuse an existing SMB connection to the same\nserver that was using a different \u0026apos;share\u0026apos; than the new subsequent transfer\nshould.\n\nThis could in unlucky situations lead to the download of the wrong file or the\nupload of a file to the wrong place. When this happens, the same credentials\nare used and the server name is the same.(CVE-2026-5773)\n\ncurl might erroneously pass on credentials for a first proxy to a second\nproxy.\n\nThis can happen when the following conditions are true:\n\n1. curl is setup to use specific different proxies for different URL schemes\n2. the first proxy needs credentials\n3. the second proxy uses no credentials\n4. while using the first proxy (using say `http://`), curl is asked to follow\n   a redirect to a URL using another scheme (say `https://`), accessed using a\n   second, different, proxy(CVE-2026-6253)\n\nUsing libcurl, when a custom `Host:` header is first set for an HTTP request\nand a second request is subsequently done using the same *easy handle* but\nwithout the custom `Host:` header set, the second request would use stale\ninformation and pass on cookies meant for the first host in the second\nrequest. Leak them.(CVE-2026-6276)\n\nWhen asked to both use a `.netrc` file for credentials and to follow HTTP\nredirects, libcurl could leak the password used for the first host to the\nfollowed-to host under certain circumstances.(CVE-2026-6429)\n\nSuccessfully using libcurl to do a transfer over a specific HTTP proxy\n(`proxyA`) with **Digest** authentication and then changing the proxy host to\na second one (`proxyB`) for a second transfer, reusing the same handle, makes\nlibcurl wrongly pass on the `Proxy-Authorization:` header field meant for\n`proxyA`, to `proxyB`.(CVE-2026-7168)",
  "id": "OESA-2026-2451",
  "modified": "2026-08-06T11:11:24Z",
  "published": "2026-05-22T11:11:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-2451"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4873"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-5545"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-5773"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6253"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6276"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6429"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-7168"
    }
  ],
  "schema_version": "1.7.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "curl security update",
  "upstream": [
    "CVE-2026-4873",
    "CVE-2026-5545",
    "CVE-2026-5773",
    "CVE-2026-6253",
    "CVE-2026-6276",
    "CVE-2026-6429",
    "CVE-2026-7168"
  ]
}



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