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CVE Record

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

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

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can leak small amounts of memory when VLAN link creation fails partway through processing egress priority settings. The source describes a reliability and resource-management bug, not data theft or remote code execution. Business urgency depends on kernel exposure and whether untrusted users can reach network link administration paths.

Executive priority

Treat this as a patch-cycle reliability issue unless local exposure is unusually broad. Prioritize routine kernel updates on systems using VLANs or delegated network administration, but the provided evidence does not support emergency handling.

Technical view

The bug is in vlan_newlink()/vlan_changelink(): if a later allocation fails after earlier egress priority allocations succeed, cleanup was missed. The kernel fix frees previously allocated VLAN egress priority entries after failed newlink handling because normal device cleanup callbacks are not invoked on that failure path.

Likely exposure

Exposure is limited to Linux systems running affected kernel builds with VLAN support. The source lists affected kernel versions including 5.17, 5.4.292, 5.10.236, 5.15.180, 5.18.13, and 5.19, but distro backport status must be verified separately.

Exploitation context

The source includes a syzbot memory-leak report and marks KEV as false. There is no cited evidence of active exploitation, public weaponization, remote reachability, privilege requirements, or impact beyond memory leakage under allocation-failure conditions.

Researcher notes

The key condition is failed allocation during VLAN changelink/newlink after prior egress priority allocations. The source does not provide CVSS, CWE, privilege requirements, or exploit status beyond syzbot discovery and stable kernel fixes.

Mitigation direction

  • Update to a kernel build containing the referenced stable fixes.
  • Check Linux distribution advisories for backported fixes and package names.
  • Prioritize hosts using VLAN networking or container/network orchestration features.
  • Restrict network link administration to trusted operators where practical.

Validation and detection

  • Inventory kernel versions and compare them with the CVE record's affected list.
  • Confirm whether vendor kernel packages include one of the referenced stable commits.
  • Review systems that permit VLAN link creation or change operations.
  • Track regression testing around VLAN configuration after kernel updates.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
6Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxb195d229de401377f70c04e0dff93b342464ec8e, 62d7ad2c191122119c66361ba6d9f04974b51afe, 842801181864690fdcde73b017cce4c1353a7083, 37aa50c539bcbcc01767e515bd170787fcfc0f33, 37aa50c539bcbcc01767e515bd170787fcfc0f33unaffected
LinuxLinux5.17, 0, 5.4.292, 5.10.236, 5.15.180, 5.18.13, 5.19affected
Weakness

CWE details

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