{
  "document": {
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      "text": "Moderate"
    },
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Copyright \u00a9 Red Hat, Inc. All rights reserved.",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en",
    "notes": [
      {
        "category": "summary",
        "text": "An update for perl-CPAN is now available for Red Hat Enterprise Linux 8.\n\nRed Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.",
        "title": "Topic"
      },
      {
        "category": "general",
        "text": "The CPAN module is a tool to query, download and build perl modules from CPAN sites.\n\nSecurity Fix(es):\n\n* perl-CPAN: Bypass of verification of signatures in CHECKSUMS files (CVE-2020-16156)\n\nFor more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.",
        "title": "Details"
      },
      {
        "category": "legal_disclaimer",
        "text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.",
        "title": "Terms of Use"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "https://access.redhat.com/security/team/contact/",
      "issuing_authority": "Red Hat Product Security is responsible for vulnerability handling across all Red Hat products and services.",
      "name": "Red Hat Product Security",
      "namespace": "https://www.redhat.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "https://access.redhat.com/errata/RHSA-2025:8432",
        "url": "https://access.redhat.com/errata/RHSA-2025:8432"
      },
      {
        "category": "external",
        "summary": "https://access.redhat.com/security/updates/classification/#moderate",
        "url": "https://access.redhat.com/security/updates/classification/#moderate"
      },
      {
        "category": "external",
        "summary": "2035273",
        "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2035273"
      },
      {
        "category": "self",
        "summary": "Canonical URL",
        "url": "https://security.access.redhat.com/data/csaf/v2/advisories/2025/rhsa-2025_8432.json"
      }
    ],
    "title": "Red Hat Security Advisory: perl-CPAN security update",
    "tracking": {
      "current_release_date": "2025-12-12T08:25:13+00:00",
      "generator": {
        "date": "2025-12-12T08:25:13+00:00",
        "engine": {
          "name": "Red Hat SDEngine",
          "version": "4.6.13"
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      },
      "id": "RHSA-2025:8432",
      "initial_release_date": "2025-06-03T07:45:18+00:00",
      "revision_history": [
        {
          "date": "2025-06-03T07:45:18+00:00",
          "number": "1",
          "summary": "Initial version"
        },
        {
          "date": "2025-06-03T07:45:18+00:00",
          "number": "2",
          "summary": "Last updated version"
        },
        {
          "date": "2025-12-12T08:25:13+00:00",
          "number": "3",
          "summary": "Last generated version"
        }
      ],
      "status": "final",
      "version": "3"
    }
  },
  "product_tree": {
    "branches": [
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        "branches": [
          {
            "branches": [
              {
                "category": "product_name",
                "name": "Red Hat Enterprise Linux AppStream (v. 8)",
                "product": {
                  "name": "Red Hat Enterprise Linux AppStream (v. 8)",
                  "product_id": "AppStream-8.10.0.Z.MAIN.EUS",
                  "product_identification_helper": {
                    "cpe": "cpe:/a:redhat:enterprise_linux:8::appstream"
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            "name": "Red Hat Enterprise Linux"
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                "name": "perl-CPAN-0:2.18-402.el8_10.src",
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                  "product_id": "perl-CPAN-0:2.18-402.el8_10.src",
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                    "purl": "pkg:rpm/redhat/perl-CPAN@2.18-402.el8_10?arch=src"
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            "name": "src"
          },
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                "name": "perl-CPAN-0:2.18-402.el8_10.noarch",
                "product": {
                  "name": "perl-CPAN-0:2.18-402.el8_10.noarch",
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    "relationships": [
      {
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        "full_product_name": {
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          "product_id": "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.noarch"
        },
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        "relates_to_product_reference": "AppStream-8.10.0.Z.MAIN.EUS"
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  "vulnerabilities": [
    {
      "cve": "CVE-2020-16156",
      "cwe": {
        "id": "CWE-347",
        "name": "Improper Verification of Cryptographic Signature"
      },
      "discovery_date": "2021-12-13T00:00:00+00:00",
      "ids": [
        {
          "system_name": "Red Hat Bugzilla ID",
          "text": "2035273"
        }
      ],
      "notes": [
        {
          "category": "description",
          "text": "A flaw was found in the way the perl-CPAN performed verification of package signatures stored in CHECKSUMS files. A malicious or compromised CPAN server used by a user, or a man-in-the-middle attacker, could use this flaw to bypass signature verification.",
          "title": "Vulnerability description"
        },
        {
          "category": "summary",
          "text": "perl-CPAN: Bypass of verification of signatures in CHECKSUMS files",
          "title": "Vulnerability summary"
        },
        {
          "category": "other",
          "text": "This vulnerability is assigned a Moderate Severity rating primarily because of the multistep nature of the attack and the efficacy of environmental security controls. The underlying issue is a serious software flaw, designated as CWE 347: Improper Verification of Cryptographic Signature, which means the system fails to correctly verify the digital authenticity of installation packages, potentially allowing an attacker to insert malicious software into the $\\text{CPAN}$ repository. However, successfully exploiting this flaw requires a complex attack chain: the adversary must first gain control of a legitimate $\\text{CPAN}$ distribution mirror and then actively deceive a targeted user into initiating an install from that compromised source, which necessitates User Interaction. Although the potential impact of a successful attack is high (leading to a complete compromise of the victim\u0027s data and system integrity), the severity is downgraded to Moderate in secure, regulated environments. This is because mandatory defenses  such as enforcing secure $\\text{HTTPS/TLS}$ connections, implementing Multi Factor Authentication ($\\text{MFA}$), adhering to $\\text{least privilege}$ access principles, and mandating the use of $\\text{FIPS}$ validated cryptographic modules create robust, layered barriers that significantly increase the difficulty of both the required initial compromise and the necessary social engineering of a protected user, thus lowering the overall practical risk.",
          "title": "Statement"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product\u0027s status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
      "product_status": {
        "fixed": [
          "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.noarch",
          "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.src"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "Canonical URL",
          "url": "https://access.redhat.com/security/cve/CVE-2020-16156"
        },
        {
          "category": "external",
          "summary": "RHBZ#2035273",
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2035273"
        },
        {
          "category": "external",
          "summary": "https://www.cve.org/CVERecord?id=CVE-2020-16156",
          "url": "https://www.cve.org/CVERecord?id=CVE-2020-16156"
        },
        {
          "category": "external",
          "summary": "https://nvd.nist.gov/vuln/detail/CVE-2020-16156",
          "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-16156"
        },
        {
          "category": "external",
          "summary": "http://blogs.perl.org/users/neilb/2021/11/addressing-cpan-vulnerabilities-related-to-checksums.html",
          "url": "http://blogs.perl.org/users/neilb/2021/11/addressing-cpan-vulnerabilities-related-to-checksums.html"
        },
        {
          "category": "external",
          "summary": "https://blog.hackeriet.no/cpan-signature-verification-vulnerabilities/",
          "url": "https://blog.hackeriet.no/cpan-signature-verification-vulnerabilities/"
        }
      ],
      "release_date": "2021-11-23T00:00:00+00:00",
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2025-06-03T07:45:18+00:00",
          "details": "For details on how to apply this update, which includes the changes described in this advisory, refer to:\n\nhttps://access.redhat.com/articles/11258",
          "product_ids": [
            "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.noarch",
            "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.src"
          ],
          "restart_required": {
            "category": "none"
          },
          "url": "https://access.redhat.com/errata/RHSA-2025:8432"
        },
        {
          "category": "workaround",
          "details": "This issue can be mitigated by configuring perl-CPAN to only use trusted CPAN mirrors (www.cpan.org or cpan.metacpan.org) and use HTTPS for communication with CPAN servers.  If you already have a cpan configured, the list of configured mirrors can be viewed by running the `cpan` command without any argument and entering the following command on the cpan command\u0027s prompt:\n\n```\n  o conf urllist\n```\n\nEnsure that the URL list only includes trusted mirrors and that https:// scheme is used for all URLs.  A different set of mirrors can be configured using the following commands (these examples show how to configure one or more mirrors, only one of the commands should be used):\n\n```\n  o conf urllist https://www.cpan.org\n  o conf urllist https://www.cpan.org https://cpan.metacpan.org\n```\n\nAfter changing configuration, the following command must be used to save the configuration:\n\n```\n  o conf commit\n```",
          "product_ids": [
            "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.noarch",
            "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.src"
          ]
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
            "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.noarch",
            "AppStream-8.10.0.Z.MAIN.EUS:perl-CPAN-0:2.18-402.el8_10.src"
          ]
        }
      ],
      "threats": [
        {
          "category": "impact",
          "details": "Moderate"
        }
      ],
      "title": "perl-CPAN: Bypass of verification of signatures in CHECKSUMS files"
    }
  ]
}