CVE-2021-26855: microsoft exchange server

csirt@kutim:~/threat-intel/cve/CVE-2021-26855

CVSS 9.1 · Critical KEV · sudah dieksploitasi Dipakai ransomware EPSS 100,0%

Kerentanan Server-Side Request Forgery (SSRF) pada microsoft exchange server. Skor CVSS 3.1 9.1 (Critical) menurut microsoft.com. Masuk katalog KEV CISA pada 3 November 2021, artinya sudah terbukti dieksploitasi. Tercatat dipakai dalam kampanye ransomware.

Deskripsi (NVD)

Microsoft Exchange Server Remote Code Execution Vulnerability

Rincian

Terbit di NVD: 3 Maret 2021
Terakhir diubah: 19 Agustus 2026
Status NVD: Analyzed
CVSS 3.1: 9.1 (Critical), sumber microsoft.com
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N · uraikan di kalkulator
Jenis kelemahan (CWE): CWE-918: Server-Side Request Forgery (SSRF)
EPSS (30 hari): 100,0% peluang dieksploitasi; lebih tinggi dari 99,9% CVE lain

Known Exploited Vulnerabilities (CISA)

Nama: Microsoft Exchange Server Remote Code Execution Vulnerability
Masuk KEV: 3 November 2021
Tenggat CISA: 3 Mei 2022 (untuk instansi federal AS)
Ransomware: Tercatat dipakai dalam kampanye ransomware
Tindakan wajib: Apply updates per vendor instructions.

Produk dan versi terdampak

Vendor	Produk	Versi terdampak
microsoft	exchange server	Versi 2013 cumulative_update_21
microsoft	exchange server	Versi 2013 cumulative_update_22
microsoft	exchange server	Versi 2013 cumulative_update_23
microsoft	exchange server	Versi 2016 cumulative_update_10
microsoft	exchange server	Versi 2016 cumulative_update_11
microsoft	exchange server	Versi 2016 cumulative_update_12
microsoft	exchange server	Versi 2016 cumulative_update_13
microsoft	exchange server	Versi 2016 cumulative_update_14
microsoft	exchange server	Versi 2016 cumulative_update_15
microsoft	exchange server	Versi 2016 cumulative_update_16
microsoft	exchange server	Versi 2016 cumulative_update_17
microsoft	exchange server	Versi 2016 cumulative_update_18
microsoft	exchange server	Versi 2016 cumulative_update_19
microsoft	exchange server	Versi 2016 cumulative_update_8
microsoft	exchange server	Versi 2016 cumulative_update_9
microsoft	exchange server	Versi 2019
microsoft	exchange server	Versi 2019 cumulative_update_1
microsoft	exchange server	Versi 2019 cumulative_update_2
microsoft	exchange server	Versi 2019 cumulative_update_3
microsoft	exchange server	Versi 2019 cumulative_update_4
microsoft	exchange server	Versi 2019 cumulative_update_5
microsoft	exchange server	Versi 2019 cumulative_update_6
microsoft	exchange server	Versi 2019 cumulative_update_7
microsoft	exchange server	Versi 2019 cumulative_update_8

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26855 patch · advisory vendor
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855 patch · advisory vendor
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26855 pemerintah AS
http://packetstormsecurity.com/files/161846/Microsoft-Exchange-2019-SSRF-Arbitrary-File-Write.html exploit · advisory pihak ketiga · vdb entry
http://packetstormsecurity.com/files/161938/Microsoft-Exchange-ProxyLogon-Remote-Code-Execution.html exploit · advisory pihak ketiga · vdb entry
http://packetstormsecurity.com/files/162610/Microsoft-Exchange-2019-Unauthenticated-Email-Download.html exploit · advisory pihak ketiga · vdb entry
http://packetstormsecurity.com/files/162736/Microsoft-Exchange-ProxyLogon-Collector.html exploit · advisory pihak ketiga · vdb entry

Sumber: NVD · CVE.org · KEV CISA · EPSS. Halaman ini disusun otomatis dari data tersebut; pembaruan terakhir 5 Okt 2026, 20:10 WITA. Kalau sistem di Perangkat Daerah memakai produk ini dan butuh bantuan, laporkan lewat kanal pelaporan.