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CVE-2026-52925

Full vulnerability record from the local CVENow database.

Description

In 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: <TASK> 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)

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Analyzed
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-24 08:16:22.563000
Last modified
2026-11-06 17:17:56.400000
View original CVE JSON 
{
  "id": "CVE-2026-52925",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-06-24T08:16:22.563",
  "lastModified": "2026-11-06T17:17:56.400",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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<TASK>\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)"
    }
  ],
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            },
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              "versionType": "original_commit_for_fix",
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      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
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    "ssvcV203": [
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          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-476"
        }
      ]
    }
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