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      "text" : "An updated version of Red Hat Update Infrastructure (RHUI) is now\navailable. RHUI 4.11.4 resolves a security vulnerability in pyOpenSSL.",
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      "text" : "Red Hat Update Infrastructure (RHUI) provides a highly scalable and redundant framework for managing repositories and content. It also allows cloud providers to deliver content and updates to Red Hat Enterprise Linux (RHEL) instances.\n\nSecurity Fixes:\n* pyOpenSSL: DTLS cookie callback buffer overflow (CVE-2026-27459)",
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      "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.",
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    "title" : "Red Hat Security Advisory: RHUI 4.11.4 security update - python-pyOpenSSL",
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      "name" : "Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')"
    },
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    "ids" : [ {
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      "text" : "2448503"
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    "notes" : [ {
      "category" : "description",
      "text" : "A flaw was found in pyOpenSSL. The set_cookie_generate_callback callback function can be used to generate DTLS cookies. When the callback returns a cookie string or byte sequence longer than 256 bytes, a buffer overflow can be triggered due to a missing bounds checking before copying the data to a fixed-size buffer provided by the underlying OpenSSL library.",
      "title" : "Vulnerability description"
    }, {
      "category" : "summary",
      "text" : "pyOpenSSL: DTLS cookie callback buffer overflow",
      "title" : "Vulnerability summary"
    }, {
      "category" : "other",
      "text" : "This flaw is only exploitable when an application using the pyOpenSSL library provides a custom callback to the set_cookie_generate_callback function. For the buffer overflow to occur, the callback function must return a cookie string or byte sequence longer than 256 bytes, limiting the exposure of this issue. Due to these reasons, this vulnerability has been rated with an important severity.",
      "title" : "Statement"
    }, {
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      "text" : "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
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    } ],
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      "summary" : "https://www.cve.org/CVERecord?id=CVE-2026-27459",
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      "summary" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27459",
      "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27459"
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      "category" : "external",
      "summary" : "https://github.com/pyca/pyopenssl/blob/358cbf29c4e364c59930e53a270116249581eaa3/CHANGELOG.rst",
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      "summary" : "https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408",
      "url" : "https://github.com/pyca/pyopenssl/commit/57f09bb4bb051d3bc2a1abd36e9525313d5cd408"
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      "summary" : "https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4",
      "url" : "https://github.com/pyca/pyopenssl/security/advisories/GHSA-5pwr-322w-8jr4"
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    "release_date" : "2026-03-17T23:34:28.483000+00:00",
    "remediations" : [ {
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      "date" : "2026-04-27T10:15:08+00:00",
      "details" : "Before applying this update, make sure all previously released errata relevant\nto your system have been applied.\n\nFor detailed instructions on how to apply this update, see:\nhttps://docs.redhat.com/en/documentation/red_hat_update_infrastructure/4/html/migrating_red_hat_update_infrastructure/assembly_upgrading-red-hat-update-infrastructure_migrating-red-hat-update-infrastructure\n\nNote: While there is no updated version of rhui-installer, for this update to take effect, it is necessary to rerun rhui-installer on the RHUA node and to reinstall the CDS nodes, as described in the documentation.\n\nFor other information, see the product documentation:\nhttps://docs.redhat.com/en/documentation/red_hat_update_infrastructure/4",
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      },
      "url" : "https://access.redhat.com/errata/RHSA-2026:10754"
    }, {
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      "details" : "To mitigate this flaw, ensure the callback provided to the set_cookie_generate_callback function strictly limits the returned cookie string or byte sequence to under 256 bytes.",
      "product_ids" : [ "8Base-RHUI-4:python-pyOpenSSL-0:24.1.0-2.el8ui.src", "8Base-RHUI-4:python3.11-pyOpenSSL-0:24.1.0-2.el8ui.noarch" ]
    } ],
    "scores" : [ {
      "cvss_v3" : {
        "attackComplexity" : "HIGH",
        "attackVector" : "NETWORK",
        "availabilityImpact" : "HIGH",
        "baseScore" : 8.1,
        "baseSeverity" : "HIGH",
        "confidentialityImpact" : "HIGH",
        "integrityImpact" : "HIGH",
        "privilegesRequired" : "NONE",
        "scope" : "UNCHANGED",
        "userInteraction" : "NONE",
        "vectorString" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
        "version" : "3.1"
      },
      "products" : [ "8Base-RHUI-4:python-pyOpenSSL-0:24.1.0-2.el8ui.src", "8Base-RHUI-4:python3.11-pyOpenSSL-0:24.1.0-2.el8ui.noarch" ]
    } ],
    "threats" : [ {
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      "details" : "Important"
    } ],
    "title" : "pyOpenSSL: DTLS cookie callback buffer overflow"
  } ]
}