{
    "id": "CVE-2021-26855",
    "published": "2021-03-03 00:15:12",
    "last_modified": "2026-08-19 19:22:24",
    "cvss_score": "9.1",
    "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:N",
    "cwe": "CWE-918",
    "description": "Microsoft Exchange Server Remote Code Execution Vulnerability",
    "epss_score": "0.99996",
    "epss_percentile": "0.99988",
    "kev": 1,
    "kev_due": "2022-05-03",
    "has_exploit": 1,
    "updated_at": "2026-09-26 18:27:08",
    "priority": {
        "rank": 1,
        "label": "Patch first",
        "why": "On CISA KEV — known exploited in the wild, due 2022-05-03."
    },
    "products": [
        {
            "vendor": "microsoft",
            "product": "exchange_server"
        }
    ],
    "kev_detail": {
        "cve_id": "CVE-2021-26855",
        "date_added": "2021-11-03",
        "due_date": "2022-05-03",
        "vendor": "Microsoft",
        "product": "Exchange Server",
        "name": "Microsoft Exchange Server Remote Code Execution Vulnerability",
        "ransomware": 1
    },
    "exploits": [
        {
            "source": "exploit-db",
            "ref_id": "49895",
            "title": "Microsoft Exchange 2019 - Unauthenticated Email Download (Metasploit)",
            "date": "2021-05-21",
            "url": "https://www.exploit-db.com/exploits/49895"
        },
        {
            "source": "exploit-db",
            "ref_id": "49879",
            "title": "Microsoft Exchange 2019 - Unauthenticated Email Download",
            "date": "2021-05-18",
            "url": "https://www.exploit-db.com/exploits/49879"
        },
        {
            "source": "exploit-db",
            "ref_id": "49663",
            "title": "Microsoft Exchange 2019 - Server-Side Request Forgery",
            "date": "2021-03-14",
            "url": "https://www.exploit-db.com/exploits/49663"
        },
        {
            "source": "exploit-db",
            "ref_id": "49637",
            "title": "Microsoft Exchange 2019 - Server-Side Request Forgery (Proxylogon) (PoC)",
            "date": "2021-03-11",
            "url": "https://www.exploit-db.com/exploits/49637"
        }
    ],
    "refs_list": [
        "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26855",
        "http://packetstormsecurity.com/files/161846/Microsoft-Exchange-2019-SSRF-Arbitrary-File-Write.html",
        "http://packetstormsecurity.com/files/161938/Microsoft-Exchange-ProxyLogon-Remote-Code-Execution.html",
        "http://packetstormsecurity.com/files/162610/Microsoft-Exchange-2019-Unauthenticated-Email-Download.html",
        "http://packetstormsecurity.com/files/162736/Microsoft-Exchange-ProxyLogon-Collector.html",
        "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855",
        "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855"
    ]
}