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    CVE-2018-20843

    In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).

    Published:Jun 24, 2019
    Last Modified:May 30, 2025
    EPS:Jun 24, 2019
    EPSS Score:0.05817
    CVSS Score:7.5

    Affected Products

    Vendor
    Canonical
    Product
    Ubuntu Linux
    Vendor
    Debian
    Product
    Debian Linux
    Vendor
    Fedoraproject
    Product
    Fedora
    Vendor
    Libexpat Project
    Product
    Libexpat
    Vendor
    Opensuse
    Product
    Leap
    Vendor
    Oracle
    Product
    Hospitality Res 3700
    Vendor
    Oracle
    Product
    Http Server
    Vendor
    Oracle
    Product
    Outside In Technology
    Vendor
    Redhat
    Product
    Enterprise Linux
    Vendor
    Redhat
    Product
    Jboss Core Services
    Vendor
    Redhat
    Product
    Openshift Do
    Vendor
    Tenable
    Product
    Nessus

    Exploits

    https://github.com/libexpat/libexpat/pull/262https://github.com/libexpat/libexpat/pull/262

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    CVE-2026-47336 (CVSS 3.3) — Ubuntu Linux 6.8 contains SAUCE patches with a possible use of an uninitialized variable in AppArmor AF_INET/A…
    CVE-2026-47335 (CVSS 5.5) — Ubuntu Linux 6.8 contains SAUCE patches with a possible NULL pointer dereference in the handling of AppArmor n…
    CVE-2026-47334 (CVSS 5.5) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which incorrectly sleep while holding a spinlock…
    CVE-2026-47333 (CVSS 7.8) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which can potentially incorrectly compute the si…
    CVE-2026-47332 (CVSS 5.5) — Ubuntu Linux 6.8, 6.17 and 7.0 contain AppArmor SAUCE patches which incorrectly validate the size of an intern…
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    References

    http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.html
    https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226
    https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/Changes
    https://github.com/libexpat/libexpat/issues/186
    https://github.com/libexpat/libexpat/pull/262
    https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6
    https://lists.debian.org/debian-lts-announce/2019/06/msg00028.html
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEJJSQSG3KSUQY4FPVHZ7ZTT7FORMFVD/
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IDAUGEB3TUP6NEKJDBUBZX7N5OAUOOOK/
    https://seclists.org/bugtraq/2019/Jun/39
    https://security.gentoo.org/glsa/201911-08
    https://security.netapp.com/advisory/ntap-20190703-0001/
    https://support.f5.com/csp/article/K51011533
    https://usn.ubuntu.com/4040-1/
    https://usn.ubuntu.com/4040-2/
    https://www.debian.org/security/2019/dsa-4472
    https://www.oracle.com/security-alerts/cpuApr2021.html
    https://www.oracle.com/security-alerts/cpuapr2020.html
    https://www.oracle.com/security-alerts/cpuoct2020.html
    https://www.oracle.com/security-alerts/cpuoct2021.html
    https://www.tenable.com/security/tns-2021-11
    http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00039.html
    https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5226
    https://github.com/libexpat/libexpat/blob/R_2_2_7/expat/Changes
    https://github.com/libexpat/libexpat/issues/186
    https://github.com/libexpat/libexpat/pull/262
    https://github.com/libexpat/libexpat/pull/262/commits/11f8838bf99ea0a6f0b76f9760c43704d00c4ff6
    https://lists.debian.org/debian-lts-announce/2019/06/msg00028.html
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CEJJSQSG3KSUQY4FPVHZ7ZTT7FORMFVD/
    https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IDAUGEB3TUP6NEKJDBUBZX7N5OAUOOOK/
    https://seclists.org/bugtraq/2019/Jun/39
    https://security.gentoo.org/glsa/201911-08
    https://security.netapp.com/advisory/ntap-20190703-0001/
    https://support.f5.com/csp/article/K51011533
    https://usn.ubuntu.com/4040-1/
    https://usn.ubuntu.com/4040-2/
    https://www.debian.org/security/2019/dsa-4472
    https://www.oracle.com/security-alerts/cpuApr2021.html
    https://www.oracle.com/security-alerts/cpuapr2020.html
    https://www.oracle.com/security-alerts/cpuoct2020.html
    https://www.oracle.com/security-alerts/cpuoct2021.html
    https://www.tenable.com/security/tns-2021-11

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High