CVE-2026-76956

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{"bugzilla": {"description": "libexpat: libexpat: Denial of Service via hash flooding attack with crafted XML", "id": "2520124", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2520124"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.9", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-331", "details": ["In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code leads to insufficient entropy, which results in being vulnerable to hash flooding attacks, causing a denial of service via crafted XML content.", "A flaw was found in libexpat. This vulnerability arises from the software misinterpreting a return code, leading to insufficient randomness (entropy) for hash functions. A remote attacker could exploit this by sending specially crafted XML content, triggering hash flooding attacks. This can result in a denial of service (DoS), making the affected system or application unavailable to legitimate users."], "mitigation": {"lang": "en:us", "value": "There is no mitigation for this flaw other than updating to libexpat 2.8.4 or later."}, "name": "CVE-2026-76956", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "expat", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "compat-expat1", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "expat", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "expat", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "expat", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "mingw-expat", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "xmlrpc-c", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "expat", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "expat", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-08-20T04:22:51Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-76956\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-76956\nhttps://github.com/libexpat/libexpat/pull/1326"], "statement": "Red Hat ships libexpat (packaged as \"expat\") across many products. This vulnerability was introduced in libexpat 2.8.2. Most Red Hat products ship expat versions prior to 2.8.2 and are therefore not affected. Only products shipping expat 2.8.2 or 2.8.3 are vulnerable to this hash flooding denial of service.", "threat_severity": "Moderate"}

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