FKIE_CVE-2025-39980

Vulnerability from fkie_nvd - Published: 2025-10-15 08:15 - Updated: 2026-06-17 09:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: nexthop: Forbid FDB status change while nexthop is in a group The kernel forbids the creation of non-FDB nexthop groups with FDB nexthops: # ip nexthop add id 1 via 192.0.2.1 fdb # ip nexthop add id 2 group 1 Error: Non FDB nexthop group cannot have fdb nexthops. And vice versa: # ip nexthop add id 3 via 192.0.2.2 dev dummy1 # ip nexthop add id 4 group 3 fdb Error: FDB nexthop group can only have fdb nexthops. However, as long as no routes are pointing to a non-FDB nexthop group, the kernel allows changing the type of a nexthop from FDB to non-FDB and vice versa: # ip nexthop add id 5 via 192.0.2.2 dev dummy1 # ip nexthop add id 6 group 5 # ip nexthop replace id 5 via 192.0.2.2 fdb # echo $? 0 This configuration is invalid and can result in a NPD [1] since FDB nexthops are not associated with a nexthop device: # ip route add 198.51.100.1/32 nhid 6 # ping 198.51.100.1 Fix by preventing nexthop FDB status change while the nexthop is in a group: # ip nexthop add id 7 via 192.0.2.2 dev dummy1 # ip nexthop add id 8 group 7 # ip nexthop replace id 7 via 192.0.2.2 fdb Error: Cannot change nexthop FDB status while in a group. [1] BUG: kernel NULL pointer dereference, address: 00000000000003c0 [...] Oops: Oops: 0000 [#1] SMP CPU: 6 UID: 0 PID: 367 Comm: ping Not tainted 6.17.0-rc6-virtme-gb65678cacc03 #1 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014 RIP: 0010:fib_lookup_good_nhc+0x1e/0x80 [...] Call Trace: <TASK> fib_table_lookup+0x541/0x650 ip_route_output_key_hash_rcu+0x2ea/0x970 ip_route_output_key_hash+0x55/0x80 __ip4_datagram_connect+0x250/0x330 udp_connect+0x2b/0x60 __sys_connect+0x9c/0xd0 __x64_sys_connect+0x18/0x20 do_syscall_64+0xa4/0x2a0 entry_SYSCALL_64_after_hwframe+0x4b/0x53
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0e7bfe7a268ccbd7859730c529161cafbf44637c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/24046d31f6f92220852d393d510b6062843e3fbd
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/390b3a300d7872cef9588f003b204398be69ce08
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8dd4aa0122885f710930de135af2adc4ccc3238f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e1e87ac0daacd51f522ecd1645cd76b5809303ed
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ec428fff792b7bd15b248dafca2e654b666b1304
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f0e49fd13afe9dea7a09a1c9537fd00cea22badb
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/nexthop.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e1e87ac0daacd51f522ecd1645cd76b5809303ed",
              "status": "affected",
              "version": "38428d68719c454d269cb03b776d8a4b0ad66111",
              "versionType": "git"
            },
            {
              "lessThan": "0e7bfe7a268ccbd7859730c529161cafbf44637c",
              "status": "affected",
              "version": "38428d68719c454d269cb03b776d8a4b0ad66111",
              "versionType": "git"
            },
            {
              "lessThan": "ec428fff792b7bd15b248dafca2e654b666b1304",
              "status": "affected",
              "version": "38428d68719c454d269cb03b776d8a4b0ad66111",
              "versionType": "git"
            },
            {
              "lessThan": "24046d31f6f92220852d393d510b6062843e3fbd",
              "status": "affected",
              "version": "38428d68719c454d269cb03b776d8a4b0ad66111",
              "versionType": "git"
            },
            {
              "lessThan": "f0e49fd13afe9dea7a09a1c9537fd00cea22badb",
              "status": "affected",
              "version": "38428d68719c454d269cb03b776d8a4b0ad66111",
              "versionType": "git"
            },
            {
              "lessThan": "8dd4aa0122885f710930de135af2adc4ccc3238f",
              "status": "affected",
              "version": "38428d68719c454d269cb03b776d8a4b0ad66111",
              "versionType": "git"
            },
            {
              "lessThan": "390b3a300d7872cef9588f003b204398be69ce08",
              "status": "affected",
              "version": "38428d68719c454d269cb03b776d8a4b0ad66111",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/nexthop.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "lessThan": "5.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.245",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.194",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.155",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnexthop: Forbid FDB status change while nexthop is in a group\n\nThe kernel forbids the creation of non-FDB nexthop groups with FDB\nnexthops:\n\n # ip nexthop add id 1 via 192.0.2.1 fdb\n # ip nexthop add id 2 group 1\n Error: Non FDB nexthop group cannot have fdb nexthops.\n\nAnd vice versa:\n\n # ip nexthop add id 3 via 192.0.2.2 dev dummy1\n # ip nexthop add id 4 group 3 fdb\n Error: FDB nexthop group can only have fdb nexthops.\n\nHowever, as long as no routes are pointing to a non-FDB nexthop group,\nthe kernel allows changing the type of a nexthop from FDB to non-FDB and\nvice versa:\n\n # ip nexthop add id 5 via 192.0.2.2 dev dummy1\n # ip nexthop add id 6 group 5\n # ip nexthop replace id 5 via 192.0.2.2 fdb\n # echo $?\n 0\n\nThis configuration is invalid and can result in a NPD [1] since FDB\nnexthops are not associated with a nexthop device:\n\n # ip route add 198.51.100.1/32 nhid 6\n # ping 198.51.100.1\n\nFix by preventing nexthop FDB status change while the nexthop is in a\ngroup:\n\n # ip nexthop add id 7 via 192.0.2.2 dev dummy1\n # ip nexthop add id 8 group 7\n # ip nexthop replace id 7 via 192.0.2.2 fdb\n Error: Cannot change nexthop FDB status while in a group.\n\n[1]\nBUG: kernel NULL pointer dereference, address: 00000000000003c0\n[...]\nOops: Oops: 0000 [#1] SMP\nCPU: 6 UID: 0 PID: 367 Comm: ping Not tainted 6.17.0-rc6-virtme-gb65678cacc03 #1 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014\nRIP: 0010:fib_lookup_good_nhc+0x1e/0x80\n[...]\nCall Trace:\n \u003cTASK\u003e\n fib_table_lookup+0x541/0x650\n ip_route_output_key_hash_rcu+0x2ea/0x970\n ip_route_output_key_hash+0x55/0x80\n __ip4_datagram_connect+0x250/0x330\n udp_connect+0x2b/0x60\n __sys_connect+0x9c/0xd0\n __x64_sys_connect+0x18/0x20\n do_syscall_64+0xa4/0x2a0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53"
    }
  ],
  "id": "CVE-2025-39980",
  "lastModified": "2026-06-17T09:18:56.983",
  "metrics": {},
  "published": "2025-10-15T08:15:35.887",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0e7bfe7a268ccbd7859730c529161cafbf44637c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/24046d31f6f92220852d393d510b6062843e3fbd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/390b3a300d7872cef9588f003b204398be69ce08"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8dd4aa0122885f710930de135af2adc4ccc3238f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e1e87ac0daacd51f522ecd1645cd76b5809303ed"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ec428fff792b7bd15b248dafca2e654b666b1304"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f0e49fd13afe9dea7a09a1c9537fd00cea22badb"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Deferred"
}


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