cbcvebase.
CVE-2021-47222
published 2024-05-21

CVE-2021-47222: In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix vlan tunnel dst refcnt when egressing The egress tunnel code uses…

PriorityP338high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.25%
15.9th percentile
In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix vlan tunnel dst refcnt when egressing The egress tunnel code uses dst_clone() and directly sets the result which is wrong because the entry might have 0 refcnt or be already deleted, causing number of problems. It also triggers the WARN_ON() in dst_hold()[1] when a refcnt couldn't be taken. Fix it by using dst_hold_safe() and checking if a reference was actually taken before setting the dst. [1] dmesg WARN_ON log and following refcnt errors WARNING: CPU: 5 PID: 38 at include/net/dst.h:230 br_handle_egress_vlan_tunnel+0x10b/0x134 [bridge] Modules linked in: 8021q garp mrp bridge stp llc bonding ipv6 virtio_net CPU: 5 PID: 38 Comm: ksoftirqd/5 Kdump: loaded Tainted: G W 5.13.0-rc3+ #360 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 RIP: 0010:br_handle_egress_vlan_tunnel+0x10b/0x134 [bridge] Code: e8 85 bc 01 e1 45 84 f6 74 90 45 31 f6 85 db 48 c7 c7 a0 02 19 a0 41 0f 94 c6 31 c9 31 d2 44 89 f6 e8 64 bc 01 e1 85 db 75 02 0b 31 c9 31 d2 44 89 f6 48 c7 c7 70 02 19 a0 e8 4b bc 01 e1 49 RSP: 0018:ffff8881003d39e8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffffa01902a0 RBP: ffff8881040c6700 R08: 0000000000000000 R09: 0000000000000001 R10: 2ce93d0054fe0d00 R11: 54fe0d00000e0000 R12: ffff888109515000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000401 FS: 0000000000000000(0000) GS:ffff88822bf40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f42ba70f030 CR3: 0000000109926000 CR4: 00000000000006e0 Call Trace: br_handle_vlan+0xbc/0xca [bridge] __br_forward+0x23/0x164 [bridge] deliver_clone+0x41/0x48 [bridge] br_handle_frame_finish+0x36f/0x3aa [bridge] ? skb_dst+0x2e/0x38 [bridge] ? br_handle_ingress_vlan_tunnel+0x3e/0x1c8 [bridge] ? br_handle_frame_finish+0x3aa/0x3aa [bridge] br_handle_frame+0x2c3/0x377 [b

Affected

18 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.10.46-1 (bookworm)linux 5.10.46-1 (bookworm)
linuxlinux
linuxlinux>= 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd < 42020f7f37a90d24b9551f5f7eba3f7c7c10296842020f7f37a90d24b9551f5f7eba3f7c7c102968
linuxlinux>= 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd < 84fc1c944e45ab317e2e70a0e7f76fa2a5e43b6e84fc1c944e45ab317e2e70a0e7f76fa2a5e43b6e
linuxlinux>= 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd < 79855be6445b6592bddb7bd7167083ec8cdbd73f79855be6445b6592bddb7bd7167083ec8cdbd73f
linuxlinux>= 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd < fc7fdd8c5c2ad2fe3e297698be9d4dbe4a4e0579fc7fdd8c5c2ad2fe3e297698be9d4dbe4a4e0579
linuxlinux>= 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd < 25053a8404ba17ca48f5553d487afc1882e9f56c25053a8404ba17ca48f5553d487afc1882e9f56c
linuxlinux>= 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd < cfc579f9d89af4ada58c69b03bcaa4887840f3b3cfc579f9d89af4ada58c69b03bcaa4887840f3b3
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.46-15.10.46-1
linuxlinux_kernel>= 0 < 5.10.46-15.10.46-1
linuxlinux_kernel>= 0 < 5.10.46-15.10.46-1
linuxlinux_kernel>= 0 < 5.10.46-15.10.46-1
linuxlinux_kernel>= 4.11 < 4.14.2384.14.238
linuxlinux_kernel>= 4.15 < 4.19.1964.19.196
linuxlinux_kernel>= 4.20 < 5.4.1285.4.128
linuxlinux_kernel>= 5.11 < 5.12.135.12.13
linuxlinux_kernel>= 5.5 < 5.10.465.10.46

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8HIGH
vendor_redhat7.8HIGH
Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.