GHSA-VG8W-8F3P-9P3C
Vulnerability from github – Published: 2026-06-24 09:30 – Updated: 2026-06-24 09:30In the Linux kernel, the following vulnerability has been resolved:
vrf: Fix a potential NPD when removing a port from a VRF
RCU readers that identified a net device as a VRF port using netif_is_l3_slave() assume that a subsequent call to netdev_master_upper_dev_get_rcu() will return a VRF device. They then continue to dereference its l3mdev operations.
This assumption is not always correct and can result in a NPD [1]. There is no RCU synchronization when removing a port from a VRF, so it is possible for an RCU reader to see a new master device (e.g., a bridge) that does not have l3mdev operations.
Fix by adding RCU synchronization after clearing the IFF_L3MDEV_SLAVE flag. Skip this synchronization when a net device is removed from a VRF as part of its deletion and when the VRF device itself is deleted. In the latter case an RCU grace period will pass by the time RTNL is released.
[1] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] RIP: 0010:l3mdev_fib_table_rcu (net/l3mdev/l3mdev.c:181) [...] Call Trace: l3mdev_fib_table_by_index (net/l3mdev/l3mdev.c:201 net/l3mdev/l3mdev.c:189) __inet_bind (net/ipv4/af_inet.c:499 (discriminator 3)) inet_bind_sk (net/ipv4/af_inet.c:469) __sys_bind (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:1951 (discriminator 1)) __x64_sys_bind (net/socket.c:1969 (discriminator 1) net/socket.c:1967 (discriminator 1) net/socket.c:1967 (discriminator 1)) do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1)) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
{
"affected": [],
"aliases": [
"CVE-2026-52925"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-24T08:16:22Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvrf: Fix a potential NPD when removing a port from a VRF\n\nRCU readers that identified a net device as a VRF port using\nnetif_is_l3_slave() assume that a subsequent call to\nnetdev_master_upper_dev_get_rcu() will return a VRF device. They then\ncontinue to dereference its l3mdev operations.\n\nThis assumption is not always correct and can result in a NPD [1]. There\nis no RCU synchronization when removing a port from a VRF, so it is\npossible for an RCU reader to see a new master device (e.g., a bridge)\nthat does not have l3mdev operations.\n\nFix by adding RCU synchronization after clearing the IFF_L3MDEV_SLAVE\nflag. Skip this synchronization when a net device is removed from a VRF\nas part of its deletion and when the VRF device itself is deleted. In\nthe latter case an RCU grace period will pass by the time RTNL is\nreleased.\n\n[1]\nBUG: kernel NULL pointer dereference, address: 0000000000000000\n[...]\nRIP: 0010:l3mdev_fib_table_rcu (net/l3mdev/l3mdev.c:181)\n[...]\nCall Trace:\n\u003cTASK\u003e\nl3mdev_fib_table_by_index (net/l3mdev/l3mdev.c:201 net/l3mdev/l3mdev.c:189)\n__inet_bind (net/ipv4/af_inet.c:499 (discriminator 3))\ninet_bind_sk (net/ipv4/af_inet.c:469)\n__sys_bind (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:1951 (discriminator 1))\n__x64_sys_bind (net/socket.c:1969 (discriminator 1) net/socket.c:1967 (discriminator 1) net/socket.c:1967 (discriminator 1))\ndo_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))\nentry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)",
"id": "GHSA-vg8w-8f3p-9p3c",
"modified": "2026-06-24T09:30:48Z",
"published": "2026-06-24T09:30:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-52925"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2674d603a9e6970463b2b9ebcf8e31e90beae169"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2c022f582fd16a470df6ed9e7fb7e9fc48946d49"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3db8d078f7f652379ee394132b169d304f6eb4c1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/468defa0b70902a22f4478c1207624bc1b31c124"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4ab6fc60ed5a0344b60711b09bff1dc238d8d6a4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8c2b792f04a3db97c9d8d2a45817e93f8884baf5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a7a97f2303e63ede105c1d55ef53dc497364e11d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d47204c127992da0c976ac9747070a575912e0fe"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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