{
    "id": "CVE-2021-26691",
    "published": "2021-06-10 07:15:07",
    "last_modified": "2026-06-17 03:43:38",
    "cvss_score": "9.8",
    "cvss_severity": "CRITICAL",
    "cvss_version": "3.1",
    "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
    "cwe": "CWE-122",
    "description": "In Apache HTTP Server versions 2.4.0 to 2.4.46 a specially crafted SessionHeader sent by an origin server could cause a heap overflow",
    "epss_score": "0.68289",
    "epss_percentile": "0.99311",
    "kev": 0,
    "kev_due": null,
    "has_exploit": 0,
    "updated_at": "2026-09-27 18:17:29",
    "priority": {
        "rank": 2,
        "label": "Patch early",
        "why": "EPSS 68.3% — above the 10% action threshold."
    },
    "products": [
        {
            "vendor": "apache",
            "product": "http_server"
        },
        {
            "vendor": "debian",
            "product": "debian_linux"
        },
        {
            "vendor": "fedoraproject",
            "product": "fedora"
        },
        {
            "vendor": "netapp",
            "product": "cloud_backup"
        },
        {
            "vendor": "oracle",
            "product": "enterprise_manager_ops_center"
        },
        {
            "vendor": "oracle",
            "product": "instantis_enterprisetrack"
        },
        {
            "vendor": "oracle",
            "product": "secure_backup"
        },
        {
            "vendor": "oracle",
            "product": "zfs_storage_appliance_kit"
        }
    ],
    "kev_detail": null,
    "exploits": [],
    "refs_list": [
        "http://httpd.apache.org/security/vulnerabilities_24.html",
        "http://www.openwall.com/lists/oss-security/2021/06/10/7",
        "https://lists.apache.org/thread.html/r50cae1b71f1e7421069036b213c26da7d8f47dd59874e3bd956959fe%40%3Cannounce.httpd.apache.org%3E",
        "https://lists.apache.org/thread.html/r7f2b70b621651548f4b6f027552f1dd91705d7111bb5d15cda0a68dd%40%3Cdev.httpd.apache.org%3E",
        "https://lists.apache.org/thread.html/re026d3da9d7824bd93b9f871c0fdda978d960c7e62d8c43cba8d0bf3%40%3Ccvs.httpd.apache.org%3E",
        "https://lists.debian.org/debian-lts-announce/2021/07/msg00006.html",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/",
        "https://security.gentoo.org/glsa/202107-38",
        "https://security.netapp.com/advisory/ntap-20210702-0001/",
        "https://www.debian.org/security/2021/dsa-4937",
        "https://www.oracle.com/security-alerts/cpujan2022.html",
        "https://www.oracle.com/security-alerts/cpuoct2021.html",
        "http://httpd.apache.org/security/vulnerabilities_24.html",
        "http://www.openwall.com/lists/oss-security/2021/06/10/7",
        "https://lists.apache.org/thread.html/r50cae1b71f1e7421069036b213c26da7d8f47dd59874e3bd956959fe%40%3Cannounce.httpd.apache.org%3E",
        "https://lists.apache.org/thread.html/r7f2b70b621651548f4b6f027552f1dd91705d7111bb5d15cda0a68dd%40%3Cdev.httpd.apache.org%3E",
        "https://lists.apache.org/thread.html/re026d3da9d7824bd93b9f871c0fdda978d960c7e62d8c43cba8d0bf3%40%3Ccvs.httpd.apache.org%3E",
        "https://lists.debian.org/debian-lts-announce/2021/07/msg00006.html",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/",
        "https://security.gentoo.org/glsa/202107-38",
        "https://security.netapp.com/advisory/ntap-20210702-0001/",
        "https://www.debian.org/security/2021/dsa-4937",
        "https://www.oracle.com/security-alerts/cpujan2022.html"
    ]
}