CVE-2026-63385

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{"bugzilla": {"description": "libevent: Libevent: HTTP header handling bugs create risk of access control bypass.", "id": "2520666", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2520666"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.7", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L", "status": "draft"}, "cwe": "CWE-444", "details": ["Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.", "A flaw was found in libevent. The evhttp_decode_uri_internal function in http.c decodes percent-encoded %00 bytes into literal NUL characters without rejecting them, allowing an attacker to craft a URI such as /admin/secret%00.jpg where extension-based access checks see .jpg but the server processes /admin/secret, bypassing path-based access controls. Additionally, evhttp_header_is_valid_value accepts obsolete HTTP header line folding (CRLF followed by SP/HT), which RFC 9112 states new implementations should reject, creating a header injection vector in proxy chains where the frontend rejects obs-fold but libevent accepts it. This could lead to access control bypass, header injection, or request smuggling."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2026-63385", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "libevent2", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "libevent", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "libevent", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-08-20T17:55:36Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63385\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63385\nhttps://github.com/libevent/libevent/commit/758be0c0f69c1934ef9a84ab39e9f9e5fde2e6d0\nhttps://github.com/libevent/libevent/commit/9170dd35e64714613e8d13b290587cfc28e258e2\nhttps://github.com/libevent/libevent/releases/tag/release-2.1.13-stable\nhttps://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha\nhttps://github.com/libevent/libevent/security/advisories/GHSA-jcwh-pvf2-73p2"], "statement": "Red Hat Enterprise Linux, OpenShift (RHCOS), RHIVOS, and community products (Fedora, Hummingbird) ship affected versions of libevent.", "threat_severity": "Important"}

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