CVE-2022-49636 vlan: fix memory leak in vlan_newlink()

What is CVE-2022-49636?

CVE-2022-49636 is a medium-severity denial of service vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

vlan: fix memory leak in vlan_newlink()

Blamed commit added back a bug I fixed in commit 9bbd917e0bec ("vlan: fix memory leak in vlan_dev_set_egress_priority")

If a memory allocation fails in vlan_changelink() after other allocations succeeded, we need to call vlan_dev_free_egress_priority() to free all allocated memory because after a failed ->newlink() we do not call any methods like ndo_uninit() or dev->priv_destructor().

In following example, if the allocation for last element 2000:2001 fails, we need to free eight prior allocations:

ip link add link dummy0 dummy0.100 type vlan id 100 \ egress-qos-map 1:2 2:3 3:4 4:5 5:6 6:7 7:8 8:9 2000:2001

syzbot report was:

BUG: memory leak unreferenced object 0xffff888117bd1060 (size 32): comm "syz-executor408", pid 3759, jiffies 4294956555 (age 34.090s) hex dump (first 32 bytes): 09 00 00 00 00 a0 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff83fc60ad>] kmalloc include/linux/slab.h:600 [inline] [<ffffffff83fc60ad>] vlan_dev_set_egress_priority+0xed/0x170 net/8021q/vlan_dev.c:193 [<ffffffff83fc6628>] vlan_changelink+0x178/0x1d0 net/8021q/vlan_netlink.c:128 [<ffffffff83fc67c8>] vlan_newlink+0x148/0x260 net/8021q/vlan_netlink.c:185 [<ffffffff838b1278>] rtnl_newlink_create net/core/rtnetlink.c:3363 [inline] [<ffffffff838b1278>] __rtnl_newlink+0xa58/0xdc0 net/core/rtnetlink.c:3580 [<ffffffff838b1629>] rtnl_newlink+0x49/0x70 net/core/rtnetlink.c:3593 [<ffffffff838ac66c>] rtnetlink_rcv_msg+0x21c/0x5c0 net/core/rtnetlink.c:6089 [<ffffffff839f9c37>] netlink_rcv_skb+0x87/0x1d0 net/netlink/af_netlink.c:2501 [<ffffffff839f8da7>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] [<ffffffff839f8da7>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345 [<ffffffff839f9266>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921 [<ffffffff8384dbf6>] sock_sendmsg_nosec net/socket.c:714 [inline] [<ffffffff8384dbf6>] sock_sendmsg+0x56/0x80 net/socket.c:734 [<ffffffff8384e15c>] ____sys_sendmsg+0x36c/0x390 net/socket.c:2488 [<ffffffff838523cb>] ___sys_sendmsg+0x8b/0xd0 net/socket.c:2542 [<ffffffff838525b8>] __sys_sendmsg net/socket.c:2571 [inline] [<ffffffff838525b8>] __do_sys_sendmsg net/socket.c:2580 [inline] [<ffffffff838525b8>] __se_sys_sendmsg net/socket.c:2578 [inline] [<ffffffff838525b8>] __x64_sys_sendmsg+0x78/0xf0 net/socket.c:2578 [<ffffffff845ad8d5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<ffffffff845ad8d5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 [<ffffffff8460006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Weakness: CWE-401

Which versions are affected by CVE-2022-49636?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2022-49636?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2022-49636 being exploited?

There is no known exploitation of CVE-2022-49636 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-58356, DEBIAN-CVE-2022-49636, GHSA-46vm-5748-8g36, UBUNTU-CVE-2022-49636.