CVE-2025-39980 (GCVE-0-2025-39980)
Vulnerability from cvelistv5
Published
2025-10-15 07:56
Modified
2025-10-15 07:56
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
Linux Linux Version: 38428d68719c454d269cb03b776d8a4b0ad66111
Version: 38428d68719c454d269cb03b776d8a4b0ad66111
Version: 38428d68719c454d269cb03b776d8a4b0ad66111
Version: 38428d68719c454d269cb03b776d8a4b0ad66111
Version: 38428d68719c454d269cb03b776d8a4b0ad66111
Version: 38428d68719c454d269cb03b776d8a4b0ad66111
Version: 38428d68719c454d269cb03b776d8a4b0ad66111
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   Linux Linux Version: 5.8
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/nexthop.c"
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        {
          "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": [
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              "version": "5.8"
            },
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              "version": "0",
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              "version": "5.10.245",
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            },
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              "status": "unaffected",
              "version": "6.1.155",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.6.109",
              "versionType": "semver"
            },
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              "version": "6.12.50",
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              "version": "6.16.10",
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              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
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      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-10-15T07:56:00.275Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e1e87ac0daacd51f522ecd1645cd76b5809303ed"
        },
        {
          "url": "https://git.kernel.org/stable/c/0e7bfe7a268ccbd7859730c529161cafbf44637c"
        },
        {
          "url": "https://git.kernel.org/stable/c/ec428fff792b7bd15b248dafca2e654b666b1304"
        },
        {
          "url": "https://git.kernel.org/stable/c/24046d31f6f92220852d393d510b6062843e3fbd"
        },
        {
          "url": "https://git.kernel.org/stable/c/f0e49fd13afe9dea7a09a1c9537fd00cea22badb"
        },
        {
          "url": "https://git.kernel.org/stable/c/8dd4aa0122885f710930de135af2adc4ccc3238f"
        },
        {
          "url": "https://git.kernel.org/stable/c/390b3a300d7872cef9588f003b204398be69ce08"
        }
      ],
      "title": "nexthop: Forbid FDB status change while nexthop is in a group",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-39980",
    "datePublished": "2025-10-15T07:56:00.275Z",
    "dateReserved": "2025-04-16T07:20:57.150Z",
    "dateUpdated": "2025-10-15T07:56:00.275Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-39980\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-10-15T08:15:35.887\",\"lastModified\":\"2025-10-16T15:29:11.563\",\"vulnStatus\":\"Awaiting Analysis\",\"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\"}],\"metrics\":{},\"references\":[{\"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\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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