CVE-2021-3493: canonical ubuntu linux

csirt@kutim:~/threat-intel/cve/CVE-2021-3493

CVSS 7.8 · High KEV · sudah dieksploitasi EPSS 49,2%

Kerentanan Privilege Context Switching Error pada canonical ubuntu linux. Skor CVSS 3.1 7.8 (High) menurut NVD. Masuk katalog KEV CISA pada 20 Oktober 2022, artinya sudah terbukti dieksploitasi.

Deskripsi (NVD)

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.

Rincian

Terbit di NVD: 17 April 2021
Terakhir diubah: 17 Juni 2026
Status NVD: Analyzed
CVSS 3.1: 7.8 (High), sumber NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H · uraikan di kalkulator
Jenis kelemahan (CWE): CWE-270: Privilege Context Switching Error
CWE-863: Incorrect Authorization
EPSS (30 hari): 49,2% peluang dieksploitasi; lebih tinggi dari 98,8% CVE lain

Known Exploited Vulnerabilities (CISA)

Nama: Linux Kernel Privilege Escalation Vulnerability
Masuk KEV: 20 Oktober 2022
Tenggat CISA: 10 November 2022 (untuk instansi federal AS)
Ransomware: Belum tercatat
Tindakan wajib: Apply updates per vendor instructions.

Produk dan versi terdampak

Vendor	Produk	Versi terdampak
canonical	ubuntu linux	Semua versi sebelum 18.04
canonical	ubuntu linux	Versi 18.04.1 hingga sebelum 20.04
canonical	ubuntu linux	Semua versi sebelum 20.10

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

https://ubuntu.com/security/notices/USN-4917-1 advisory vendor
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca99... mailing list · patch · advisory pihak ketiga
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3493 pemerintah AS
http://packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html exploit · advisory pihak ketiga · vdb entry
http://packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html press/media coverage · advisory pihak ketiga · vdb entry
http://packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html exploit · advisory pihak ketiga · vdb entry
https://www.openwall.com/lists/oss-security/2021/04/16/1 mailing list · advisory pihak ketiga

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.