UBUNTU-CVE-2026-4873 (CVE-2026-4873)

Vulnerability from osv_ubuntu – Published: 2026-04-29 14:00 – Updated: 2026-09-28 20:25 – Source website
VLAI
Details

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.

Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
N/A (UNKNOWN)
low
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
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          {
            "binary_name": "curl",
            "binary_version": "7.35.0-1ubuntu2.20+esm23"
          },
          {
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          {
            "binary_name": "libcurl3-gnutls",
            "binary_version": "7.35.0-1ubuntu2.20+esm23"
          },
          {
            "binary_name": "libcurl3-nss",
            "binary_version": "7.35.0-1ubuntu2.20+esm23"
          }
        ],
        "priority_reason": "This flaw requires a rather special series of events to trigger. Such a series is unlikely to be used much in the wild."
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "curl",
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      },
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            }
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        }
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        "7.35.0-1ubuntu2.20+esm16",
        "7.35.0-1ubuntu2.20+esm17",
        "7.35.0-1ubuntu2.20+esm18",
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            "binary_name": "libcurl3-nss",
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        "priority_reason": "This flaw requires a rather special series of events to trigger. Such a series is unlikely to be used much in the wild."
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "curl",
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      },
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        "7.47.0-1ubuntu2.19+esm11",
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        "7.47.0-1ubuntu2.19+esm16",
        "7.47.0-1ubuntu2.19+esm17",
        "7.47.0-1ubuntu2.19+esm18",
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        ],
        "priority_reason": "This flaw requires a rather special series of events to trigger. Such a series is unlikely to be used much in the wild."
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "curl",
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      },
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        "7.58.0-2ubuntu3.16",
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        "7.58.0-2ubuntu3.20",
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        "7.58.0-2ubuntu3.22",
        "7.58.0-2ubuntu3.23",
        "7.58.0-2ubuntu3.24",
        "7.58.0-2ubuntu3.24+esm1",
        "7.58.0-2ubuntu3.24+esm2",
        "7.58.0-2ubuntu3.24+esm3",
        "7.58.0-2ubuntu3.24+esm4",
        "7.58.0-2ubuntu3.24+esm5",
        "7.58.0-2ubuntu3.24+esm7",
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        "7.58.0-2ubuntu3.24+esm10",
        "7.58.0-2ubuntu3.24+esm11",
        "7.58.0-2ubuntu3.24+esm12",
        "7.58.0-2ubuntu3.24+esm14"
      ]
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      "ecosystem_specific": {
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        ],
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      },
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      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
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            "binary_name": "curl",
            "binary_version": "7.81.0-1ubuntu1.24"
          },
          {
            "binary_name": "libcurl3-gnutls",
            "binary_version": "7.81.0-1ubuntu1.24"
          },
          {
            "binary_name": "libcurl3-nss",
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          },
          {
            "binary_name": "libcurl4",
            "binary_version": "7.81.0-1ubuntu1.24"
          }
        ],
        "priority_reason": "This flaw requires a rather special series of events to trigger. Such a series is unlikely to be used much in the wild."
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
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      },
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        "7.81.0-1ubuntu1.2",
        "7.81.0-1ubuntu1.3",
        "7.81.0-1ubuntu1.4",
        "7.81.0-1ubuntu1.6",
        "7.81.0-1ubuntu1.7",
        "7.81.0-1ubuntu1.8",
        "7.81.0-1ubuntu1.10",
        "7.81.0-1ubuntu1.11",
        "7.81.0-1ubuntu1.13",
        "7.81.0-1ubuntu1.14",
        "7.81.0-1ubuntu1.15",
        "7.81.0-1ubuntu1.16",
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    },
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        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "8.5.0-2ubuntu10.9"
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            "binary_name": "libcurl3t64-gnutls",
            "binary_version": "8.5.0-2ubuntu10.9"
          },
          {
            "binary_name": "libcurl4t64",
            "binary_version": "8.5.0-2ubuntu10.9"
          }
        ],
        "priority_reason": "This flaw requires a rather special series of events to trigger. Such a series is unlikely to be used much in the wild."
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "curl",
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        "availability": "No subscription required",
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          {
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        ],
        "priority_reason": "This flaw requires a rather special series of events to trigger. Such a series is unlikely to be used much in the wild."
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "curl",
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      },
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    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "curl",
            "binary_version": "8.18.0-1ubuntu2.1"
          },
          {
            "binary_name": "libcurl3t64-gnutls",
            "binary_version": "8.18.0-1ubuntu2.1"
          },
          {
            "binary_name": "libcurl4t64",
            "binary_version": "8.18.0-1ubuntu2.1"
          }
        ],
        "priority_reason": "This flaw requires a rather special series of events to trigger. Such a series is unlikely to be used much in the wild."
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "curl",
        "purl": "pkg:deb/ubuntu/curl@8.18.0-1ubuntu2.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
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            {
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            {
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      "versions": [
        "8.14.1-2ubuntu1",
        "8.17.0-1ubuntu1",
        "8.18.0-1ubuntu1",
        "8.18.0-1ubuntu2"
      ]
    }
  ],
  "aliases": [],
  "details": "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.",
  "id": "UBUNTU-CVE-2026-4873",
  "modified": "2026-09-28T20:25:56Z",
  "published": "2026-04-29T14:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-4873"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-4873"
    },
    {
      "type": "REPORT",
      "url": "https://curl.se/docs/CVE-2026-4873.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8227-1"
    }
  ],
  "related": [
    "USN-8227-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "low",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-4873"
  ]
}



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