GHSA-R5GH-Q6F7-7Q3V

Vulnerability from github – Published: 2026-03-20 09:32 – Updated: 2026-03-20 09:32
VLAI?
Details

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

macvlan: observe an RCU grace period in macvlan_common_newlink() error path

valis reported that a race condition still happens after my prior patch.

macvlan_common_newlink() might have made @dev visible before detecting an error, and its caller will directly call free_netdev(dev).

We must respect an RCU period, either in macvlan or the core networking stack.

After adding a temporary mdelay(1000) in macvlan_forward_source_one() to open the race window, valis repro was:

ip link add p1 type veth peer p2 ip link set address 00:00:00:00:00:20 dev p1 ip link set up dev p1 ip link set up dev p2 ip link add mv0 link p2 type macvlan mode source

(ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20 &) ; sleep 0.5 ; ping -c1 -I p1 1.2.3.4 PING 1.2.3.4 (1.2.3.4): 56 data bytes RTNETLINK answers: Invalid argument

BUG: KASAN: slab-use-after-free in macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) Read of size 8 at addr ffff888016bb89c0 by task e/175

CPU: 1 UID: 1000 PID: 175 Comm: e Not tainted 6.19.0-rc8+ #33 NONE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:123) print_report (mm/kasan/report.c:379 mm/kasan/report.c:482) ? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) kasan_report (mm/kasan/report.c:597) ? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444) ? tasklet_init (kernel/softirq.c:983) macvlan_handle_frame (drivers/net/macvlan.c:501)

Allocated by task 169: kasan_save_stack (mm/kasan/common.c:58) kasan_save_track (./arch/x86/include/asm/current.h:25 mm/kasan/common.c:70 mm/kasan/common.c:79) __kasan_kmalloc (mm/kasan/common.c:419) __kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5657 mm/slub.c:7140) alloc_netdev_mqs (net/core/dev.c:12012) rtnl_create_link (net/core/rtnetlink.c:3648) rtnl_newlink (net/core/rtnetlink.c:3830 net/core/rtnetlink.c:3957 net/core/rtnetlink.c:4072) rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)

Freed by task 169: kasan_save_stack (mm/kasan/common.c:58) kasan_save_track (./arch/x86/include/asm/current.h:25 mm/kasan/common.c:70 mm/kasan/common.c:79) kasan_save_free_info (mm/kasan/generic.c:587) __kasan_slab_free (mm/kasan/common.c:287) kfree (mm/slub.c:6674 mm/slub.c:6882) rtnl_newlink (net/core/rtnetlink.c:3845 net/core/rtnetlink.c:3957 net/core/rtnetlink.c:4072) rtnetlink_rcv_msg (net/core/rtnetlink.c:6958) netlink_rcv_skb (net/netlink/af_netlink.c:2550) netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1894) __sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206) __x64_sys_sendto (net/socket.c:2209) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23273"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-20T09:16:12Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacvlan: observe an RCU grace period in macvlan_common_newlink() error path\n\nvalis reported that a race condition still happens after my prior patch.\n\nmacvlan_common_newlink() might have made @dev visible before\ndetecting an error, and its caller will directly call free_netdev(dev).\n\nWe must respect an RCU period, either in macvlan or the core networking\nstack.\n\nAfter adding a temporary mdelay(1000) in macvlan_forward_source_one()\nto open the race window, valis repro was:\n\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\nip link add mv0 link p2 type macvlan mode source\n\n(ip link add invalid% link p2 type macvlan mode source macaddr add\n00:00:00:00:00:20 \u0026) ; sleep 0.5 ; ping -c1 -I p1 1.2.3.4\nPING 1.2.3.4 (1.2.3.4): 56 data bytes\nRTNETLINK answers: Invalid argument\n\nBUG: KASAN: slab-use-after-free in macvlan_forward_source\n(drivers/net/macvlan.c:408 drivers/net/macvlan.c:444)\nRead of size 8 at addr ffff888016bb89c0 by task e/175\n\nCPU: 1 UID: 1000 PID: 175 Comm: e Not tainted 6.19.0-rc8+ #33 NONE\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014\nCall Trace:\n\u003cIRQ\u003e\ndump_stack_lvl (lib/dump_stack.c:123)\nprint_report (mm/kasan/report.c:379 mm/kasan/report.c:482)\n? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444)\nkasan_report (mm/kasan/report.c:597)\n? macvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444)\nmacvlan_forward_source (drivers/net/macvlan.c:408 drivers/net/macvlan.c:444)\n? tasklet_init (kernel/softirq.c:983)\nmacvlan_handle_frame (drivers/net/macvlan.c:501)\n\nAllocated by task 169:\nkasan_save_stack (mm/kasan/common.c:58)\nkasan_save_track (./arch/x86/include/asm/current.h:25\nmm/kasan/common.c:70 mm/kasan/common.c:79)\n__kasan_kmalloc (mm/kasan/common.c:419)\n__kvmalloc_node_noprof (./include/linux/kasan.h:263 mm/slub.c:5657\nmm/slub.c:7140)\nalloc_netdev_mqs (net/core/dev.c:12012)\nrtnl_create_link (net/core/rtnetlink.c:3648)\nrtnl_newlink (net/core/rtnetlink.c:3830 net/core/rtnetlink.c:3957\nnet/core/rtnetlink.c:4072)\nrtnetlink_rcv_msg (net/core/rtnetlink.c:6958)\nnetlink_rcv_skb (net/netlink/af_netlink.c:2550)\nnetlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)\nnetlink_sendmsg (net/netlink/af_netlink.c:1894)\n__sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206)\n__x64_sys_sendto (net/socket.c:2209)\ndo_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)\nentry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)\n\nFreed by task 169:\nkasan_save_stack (mm/kasan/common.c:58)\nkasan_save_track (./arch/x86/include/asm/current.h:25\nmm/kasan/common.c:70 mm/kasan/common.c:79)\nkasan_save_free_info (mm/kasan/generic.c:587)\n__kasan_slab_free (mm/kasan/common.c:287)\nkfree (mm/slub.c:6674 mm/slub.c:6882)\nrtnl_newlink (net/core/rtnetlink.c:3845 net/core/rtnetlink.c:3957\nnet/core/rtnetlink.c:4072)\nrtnetlink_rcv_msg (net/core/rtnetlink.c:6958)\nnetlink_rcv_skb (net/netlink/af_netlink.c:2550)\nnetlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)\nnetlink_sendmsg (net/netlink/af_netlink.c:1894)\n__sys_sendto (net/socket.c:727 net/socket.c:742 net/socket.c:2206)\n__x64_sys_sendto (net/socket.c:2209)\ndo_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)\nentry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)",
  "id": "GHSA-r5gh-q6f7-7q3v",
  "modified": "2026-03-20T09:32:10Z",
  "published": "2026-03-20T09:32:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23273"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/19c7d8ac51988d053709c1e85bd8482076af845d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1e58ae87ad1e6e24368dea9aec9048c758cd0e2b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3d94323c80d7fc4da5f10f9bb06a45d39d5d3cc4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/721eb342d9ba19bad5c4815ea3921465158b7362"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/91e4ff8d966978901630fc29582c1a76d3c6e46c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a1f686d273d129b45712d95f4095843b864466bd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d34f7a8aa9a25b7e64e0e46e444697c0f702374d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e3f000f0dee1bfab52e2e61ca6a3835d9e187e35"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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