{
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        "purl": "pkg:apk/alpine/firefox-esr?arch=source"
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          "type": "ECOSYSTEM"
        }
      ]
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      "ecosystem_specific": {},
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        "ecosystem": "Alpine:v3.21",
        "name": "firefox-esr",
        "purl": "pkg:apk/alpine/firefox-esr?arch=source"
      },
      "ranges": [
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              "introduced": "0"
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          "type": "ECOSYSTEM"
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        "purl": "pkg:apk/alpine/firefox-esr?arch=source"
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              "introduced": "0"
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          "type": "ECOSYSTEM"
        }
      ]
    },
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      "ecosystem_specific": {},
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        "ecosystem": "Alpine:v3.23",
        "name": "firefox-esr",
        "purl": "pkg:apk/alpine/firefox-esr?arch=source"
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          "type": "ECOSYSTEM"
        }
      ]
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    {
      "ecosystem_specific": {},
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        "name": "librewolf",
        "purl": "pkg:apk/alpine/librewolf?arch=source"
      },
      "ranges": [
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          "events": [
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              "introduced": "0"
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            {
              "fixed": "94.0-r0"
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          "type": "ECOSYSTEM"
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      ]
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    {
      "ecosystem_specific": {},
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        "purl": "pkg:apk/alpine/librewolf?arch=source"
      },
      "ranges": [
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          "events": [
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              "introduced": "0"
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            {
              "fixed": "94.0-r0"
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    {
      "ecosystem_specific": {},
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        "purl": "pkg:apk/alpine/librewolf?arch=source"
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        "purl": "pkg:apk/alpine/librewolf?arch=source"
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        }
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      "ecosystem_specific": {},
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        "name": "thunderbird",
        "purl": "pkg:apk/alpine/thunderbird?arch=source"
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              "introduced": "0"
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              "fixed": "91.3.2-r0"
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        "name": "thunderbird",
        "purl": "pkg:apk/alpine/thunderbird?arch=source"
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        "name": "thunderbird",
        "purl": "pkg:apk/alpine/thunderbird?arch=source"
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        "name": "thunderbird",
        "purl": "pkg:apk/alpine/thunderbird?arch=source"
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    {
      "ecosystem_specific": {},
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        "name": "thunderbird",
        "purl": "pkg:apk/alpine/thunderbird?arch=source"
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        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.22",
        "name": "thunderbird",
        "purl": "pkg:apk/alpine/thunderbird?arch=source"
      },
      "ranges": [
        {
          "events": [
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              "introduced": "0"
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            {
              "fixed": "91.3.2-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.23",
        "name": "thunderbird",
        "purl": "pkg:apk/alpine/thunderbird?arch=source"
      },
      "ranges": [
        {
          "events": [
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              "introduced": "0"
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          "type": "ECOSYSTEM"
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  ],
  "details": "The Opportunistic Encryption feature of HTTP2 (RFC 8164) allows a connection to be transparently upgraded to TLS while retaining the visual properties of an HTTP connection, including being same-origin with unencrypted connections on port 80. However, if a second encrypted port on the same IP address (e.g. port 8443) did not opt-in to opportunistic encryption; a network attacker could forward a connection from the browser to port 443 to port 8443, causing the browser to treat the content of port 8443 as same-origin with HTTP. This was resolved by disabling the Opportunistic Encryption feature, which had low usage. This vulnerability affects Firefox \u003c 94, Thunderbird \u003c 91.3, and Firefox ESR \u003c 91.3.",
  "id": "ALPINE-CVE-2021-38507",
  "modified": "2026-11-03T06:17:58.647690906Z",
  "published": "2021-12-08T22:15:08.947Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security.alpinelinux.org/vuln/CVE-2021-38507"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2021-38507"
  ]
}