csirt@kutim:~/threat-intel/cve/CVE-2021-47555

Katalog CVE

CVSS 5.5 · Medium EPSS 0,22%

Kerentanan Integer Underflow (Wrap or Wraparound) pada linux kernel. Skor CVSS 3.1 5.5 (Medium) menurut NVD.

Deskripsi (NVD)

In the Linux kernel, the following vulnerability has been resolved: net: vlan: fix underflow for the real_dev refcnt Inject error before dev_hold(real_dev) in register_vlan_dev(), and execute the following testcase: ip link add dev dummy1 type dummy ip link add name dummy1.100 link dummy1 type vlan id 100 ip link del dev dummy1 When the dummy netdevice is removed, we will get a WARNING as following: ======================================================================= refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 2 PID: 0 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 and an endless loop of: ======================================================================= unregister_netdevice: waiting for dummy1 to become free. Usage count = -1073741824 That is because dev_put(real_dev) in vlan_dev_free() be called without dev_hold(real_dev) in register_vlan_dev(). It makes the refcnt of real_dev underflow. Move the dev_hold(real_dev) to vlan_dev_init() which is the call-back of ndo_init(). That makes dev_hold() and dev_put() for vlan's real_dev symmetrical.

Rincian

Terbit di NVD
24 Mei 2024
Terakhir diubah
4 Agustus 2026
Status NVD
Modified
CVSS 3.1
5.5 (Medium), sumber NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H · uraikan di kalkulator
Jenis kelemahan (CWE)
CWE-191: Integer Underflow (Wrap or Wraparound)
EPSS (30 hari)
0,22% peluang dieksploitasi; lebih tinggi dari 11,6% CVE lain

Produk dan versi terdampak

VendorProdukVersi terdampak
linux linux kernel Versi 5.4.160 hingga sebelum 5.4.163
linux linux kernel Versi 5.10.80 hingga sebelum 5.10.83
linux linux kernel Versi 5.14.19 hingga sebelum 5.15
linux linux kernel Versi 5.15.3 hingga sebelum 5.15.6
linux linux kernel Versi 5.16 rc1
linux linux kernel Versi 5.16 rc2

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

Sumber: NVD · CVE.org · 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.