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CVE-2025-39850 (GCVE-0-2025-39850)

Vulnerability from cvelistv5 – Published: 2025-09-19 15:26 – Updated: 2026-05-11 21:37
VLAI
Title
vxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects
Summary
In the Linux kernel, the following vulnerability has been resolved: vxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects When the "proxy" option is enabled on a VXLAN device, the device will suppress ARP requests and IPv6 Neighbor Solicitation messages if it is able to reply on behalf of the remote host. That is, if a matching and valid neighbor entry is configured on the VXLAN device whose MAC address is not behind the "any" remote (0.0.0.0 / ::). The code currently assumes that the FDB entry for the neighbor's MAC address points to a valid remote destination, but this is incorrect if the entry is associated with an FDB nexthop group. This can result in a NPD [1][3] which can be reproduced using [2][4]. Fix by checking that the remote destination exists before dereferencing it. [1] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] CPU: 4 UID: 0 PID: 365 Comm: arping Not tainted 6.17.0-rc2-virtme-g2a89cb21162c #2 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014 RIP: 0010:vxlan_xmit+0xb58/0x15f0 [...] Call Trace: <TASK> dev_hard_start_xmit+0x5d/0x1c0 __dev_queue_xmit+0x246/0xfd0 packet_sendmsg+0x113a/0x1850 __sock_sendmsg+0x38/0x70 __sys_sendto+0x126/0x180 __x64_sys_sendto+0x24/0x30 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [2] #!/bin/bash ip address add 192.0.2.1/32 dev lo ip nexthop add id 1 via 192.0.2.2 fdb ip nexthop add id 10 group 1 fdb ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 4789 proxy ip neigh add 192.0.2.3 lladdr 00:11:22:33:44:55 nud perm dev vx0 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10 arping -b -c 1 -s 192.0.2.1 -I vx0 192.0.2.3 [3] BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] CPU: 13 UID: 0 PID: 372 Comm: ndisc6 Not tainted 6.17.0-rc2-virtmne-g6ee90cb26014 #3 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1v996), BIOS 1.17.0-4.fc41 04/01/2x014 RIP: 0010:vxlan_xmit+0x803/0x1600 [...] Call Trace: <TASK> dev_hard_start_xmit+0x5d/0x1c0 __dev_queue_xmit+0x246/0xfd0 ip6_finish_output2+0x210/0x6c0 ip6_finish_output+0x1af/0x2b0 ip6_mr_output+0x92/0x3e0 ip6_send_skb+0x30/0x90 rawv6_sendmsg+0xe6e/0x12e0 __sock_sendmsg+0x38/0x70 __sys_sendto+0x126/0x180 __x64_sys_sendto+0x24/0x30 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f383422ec77 [4] #!/bin/bash ip address add 2001:db8:1::1/128 dev lo ip nexthop add id 1 via 2001:db8:1::1 fdb ip nexthop add id 10 group 1 fdb ip link add name vx0 up type vxlan id 10010 local 2001:db8:1::1 dstport 4789 proxy ip neigh add 2001:db8:1::3 lladdr 00:11:22:33:44:55 nud perm dev vx0 bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10 ndisc6 -r 1 -s 2001:db8:1::1 -w 1 2001:db8:1::3 vx0
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-01-14 19:20 UTC
CWE
  • CWE-476 - NULL Pointer Dereference
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1274e1cc42264d4e629841e4f182795cb0becfd2 , < e211e3f4199ac829bd493632efcd131d337cba9d (git)
Affected: 1274e1cc42264d4e629841e4f182795cb0becfd2 , < 8cfa0f076842f9b3b4eb52ae0e41d16e25cbf8fa (git)
Affected: 1274e1cc42264d4e629841e4f182795cb0becfd2 , < 1f5d2fd1ca04a23c18b1bde9a43ce2fa2ffa1bce (git)
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Linux Linux Affected: 5.8
Unaffected: 0 , < 5.8 (semver)
Unaffected: 6.12.46 , ≤ 6.12.* (semver)
Unaffected: 6.16.6 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects\n\nWhen the \"proxy\" option is enabled on a VXLAN device, the device will\nsuppress ARP requests and IPv6 Neighbor Solicitation messages if it is\nable to reply on behalf of the remote host. That is, if a matching and\nvalid neighbor entry is configured on the VXLAN device whose MAC address\nis not behind the \"any\" remote (0.0.0.0 / ::).\n\nThe code currently assumes that the FDB entry for the neighbor\u0027s MAC\naddress points to a valid remote destination, but this is incorrect if\nthe entry is associated with an FDB nexthop group. This can result in a\nNPD [1][3] which can be reproduced using [2][4].\n\nFix by checking that the remote destination exists before dereferencing\nit.\n\n[1]\nBUG: kernel NULL pointer dereference, address: 0000000000000000\n[...]\nCPU: 4 UID: 0 PID: 365 Comm: arping Not tainted 6.17.0-rc2-virtme-g2a89cb21162c #2 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014\nRIP: 0010:vxlan_xmit+0xb58/0x15f0\n[...]\nCall Trace:\n \u003cTASK\u003e\n dev_hard_start_xmit+0x5d/0x1c0\n __dev_queue_xmit+0x246/0xfd0\n packet_sendmsg+0x113a/0x1850\n __sock_sendmsg+0x38/0x70\n __sys_sendto+0x126/0x180\n __x64_sys_sendto+0x24/0x30\n do_syscall_64+0xa4/0x260\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n[2]\n #!/bin/bash\n\n ip address add 192.0.2.1/32 dev lo\n\n ip nexthop add id 1 via 192.0.2.2 fdb\n ip nexthop add id 10 group 1 fdb\n\n ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 4789 proxy\n\n ip neigh add 192.0.2.3 lladdr 00:11:22:33:44:55 nud perm dev vx0\n\n bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10\n\n arping -b -c 1 -s 192.0.2.1 -I vx0 192.0.2.3\n\n[3]\nBUG: kernel NULL pointer dereference, address: 0000000000000000\n[...]\nCPU: 13 UID: 0 PID: 372 Comm: ndisc6 Not tainted 6.17.0-rc2-virtmne-g6ee90cb26014 #3 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1v996), BIOS 1.17.0-4.fc41 04/01/2x014\nRIP: 0010:vxlan_xmit+0x803/0x1600\n[...]\nCall Trace:\n \u003cTASK\u003e\n dev_hard_start_xmit+0x5d/0x1c0\n __dev_queue_xmit+0x246/0xfd0\n ip6_finish_output2+0x210/0x6c0\n ip6_finish_output+0x1af/0x2b0\n ip6_mr_output+0x92/0x3e0\n ip6_send_skb+0x30/0x90\n rawv6_sendmsg+0xe6e/0x12e0\n __sock_sendmsg+0x38/0x70\n __sys_sendto+0x126/0x180\n __x64_sys_sendto+0x24/0x30\n do_syscall_64+0xa4/0x260\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\nRIP: 0033:0x7f383422ec77\n\n[4]\n #!/bin/bash\n\n ip address add 2001:db8:1::1/128 dev lo\n\n ip nexthop add id 1 via 2001:db8:1::1 fdb\n ip nexthop add id 10 group 1 fdb\n\n ip link add name vx0 up type vxlan id 10010 local 2001:db8:1::1 dstport 4789 proxy\n\n ip neigh add 2001:db8:1::3 lladdr 00:11:22:33:44:55 nud perm dev vx0\n\n bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10\n\n ndisc6 -r 1 -s 2001:db8:1::1 -w 1 2001:db8:1::3 vx0"
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      "initial_release_date": "2025-09-21T01:02:47.000Z",
      "product_status:known_affected": "22",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "vxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-39850.json",
      "version": "20"
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This can result in a\\nNPD [1][3] which can be reproduced using [2][4].\\n\\nFix by checking that the remote destination exists before dereferencing\\nit.\\n\\n[1]\\nBUG: kernel NULL pointer dereference, address: 0000000000000000\\n[...]\\nCPU: 4 UID: 0 PID: 365 Comm: arping Not tainted 6.17.0-rc2-virtme-g2a89cb21162c #2 PREEMPT(voluntary)\\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014\\nRIP: 0010:vxlan_xmit+0xb58/0x15f0\\n[...]\\nCall Trace:\\n \u003cTASK\u003e\\n dev_hard_start_xmit+0x5d/0x1c0\\n __dev_queue_xmit+0x246/0xfd0\\n packet_sendmsg+0x113a/0x1850\\n __sock_sendmsg+0x38/0x70\\n __sys_sendto+0x126/0x180\\n __x64_sys_sendto+0x24/0x30\\n do_syscall_64+0xa4/0x260\\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\\n\\n[2]\\n #!/bin/bash\\n\\n ip address add 192.0.2.1/32 dev lo\\n\\n ip nexthop add id 1 via 192.0.2.2 fdb\\n ip nexthop add id 10 group 1 fdb\\n\\n ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 4789 proxy\\n\\n ip neigh add 192.0.2.3 lladdr 00:11:22:33:44:55 nud perm dev vx0\\n\\n bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10\\n\\n arping -b -c 1 -s 192.0.2.1 -I vx0 192.0.2.3\\n\\n[3]\\nBUG: kernel NULL pointer dereference, address: 0000000000000000\\n[...]\\nCPU: 13 UID: 0 PID: 372 Comm: ndisc6 Not tainted 6.17.0-rc2-virtmne-g6ee90cb26014 #3 PREEMPT(voluntary)\\nHardware name: QEMU Standard PC (i440FX + PIIX, 1v996), BIOS 1.17.0-4.fc41 04/01/2x014\\nRIP: 0010:vxlan_xmit+0x803/0x1600\\n[...]\\nCall Trace:\\n \u003cTASK\u003e\\n dev_hard_start_xmit+0x5d/0x1c0\\n __dev_queue_xmit+0x246/0xfd0\\n ip6_finish_output2+0x210/0x6c0\\n ip6_finish_output+0x1af/0x2b0\\n ip6_mr_output+0x92/0x3e0\\n ip6_send_skb+0x30/0x90\\n rawv6_sendmsg+0xe6e/0x12e0\\n __sock_sendmsg+0x38/0x70\\n __sys_sendto+0x126/0x180\\n __x64_sys_sendto+0x24/0x30\\n do_syscall_64+0xa4/0x260\\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\\nRIP: 0033:0x7f383422ec77\\n\\n[4]\\n #!/bin/bash\\n\\n ip address add 2001:db8:1::1/128 dev lo\\n\\n ip nexthop add id 1 via 2001:db8:1::1 fdb\\n ip nexthop add id 10 group 1 fdb\\n\\n ip link add name vx0 up type vxlan id 10010 local 2001:db8:1::1 dstport 4789 proxy\\n\\n ip neigh add 2001:db8:1::3 lladdr 00:11:22:33:44:55 nud perm dev vx0\\n\\n bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10\\n\\n ndisc6 -r 1 -s 2001:db8:1::1 -w 1 2001:db8:1::3 vx0\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/net/vxlan/vxlan_core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"1274e1cc42264d4e629841e4f182795cb0becfd2\",\"lessThan\":\"e211e3f4199ac829bd493632efcd131d337cba9d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"1274e1cc42264d4e629841e4f182795cb0becfd2\",\"lessThan\":\"8cfa0f076842f9b3b4eb52ae0e41d16e25cbf8fa\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"1274e1cc42264d4e629841e4f182795cb0becfd2\",\"lessThan\":\"1f5d2fd1ca04a23c18b1bde9a43ce2fa2ffa1bce\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/net/vxlan/vxlan_core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.8\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.8\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.46\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.16.6\",\"lessThanOrEqual\":\"6.16.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.17\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"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},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"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}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-01-14T19:20:51.126279Z\",\"id\":\"CVE-2025-39850\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-476\"}]},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-476\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.8\",\"versionEndExcluding\":\"6.12.46\",\"matchCriteriaId\":\"2980C061-51F5-499C-B8BE-47E98D17CE4B\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.13\",\"versionEndExcluding\":\"6.16.6\",\"matchCriteriaId\":\"548F104C-0F08-438B-9C97-64C903F0C678\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"327D22EF-390B-454C-BD31-2ED23C998A1C\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"C730CD9A-D969-4A8E-9522-162AAF7C0EE9\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"39982C4B-716E-4B2F-8196-FA301F47807D\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*\",\"matchCriteriaId\":\"340BEEA9-D70D-4290-B502-FBB1032353B1\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/1f5d2fd1ca04a23c18b1bde9a43ce2fa2ffa1bce\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/8cfa0f076842f9b3b4eb52ae0e41d16e25cbf8fa\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/e211e3f4199ac829bd493632efcd131d337cba9d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-30T01:23:28+00:00",
      "cve": "CVE-2025-39850",
      "id": "CVE-2025-39850",
      "initial_release_date": "2025-09-19T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: vxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39850.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-31T00:18:31Z",
      "cve": "CVE-2025-39850",
      "id": "CVE-2025-39850",
      "initial_release_date": "2025-09-19T23:23:54Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "574",
      "product_status:known_not_affected": "213",
      "product_status:recommended": "464",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-39850",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-39850.json",
      "version": "51"
    },
    "vulnrichment": {
      "containers": "{\"cna\": {\"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-09-29T06:01:01.501Z\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nvxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects\\n\\nWhen the \\\"proxy\\\" option is enabled on a VXLAN device, the device will\\nsuppress ARP requests and IPv6 Neighbor Solicitation messages if it is\\nable to reply on behalf of the remote host. That is, if a matching and\\nvalid neighbor entry is configured on the VXLAN device whose MAC address\\nis not behind the \\\"any\\\" remote (0.0.0.0 / ::).\\n\\nThe code currently assumes that the FDB entry for the neighbor\u0027s MAC\\naddress points to a valid remote destination, but this is incorrect if\\nthe entry is associated with an FDB nexthop group. This can result in a\\nNPD [1][3] which can be reproduced using [2][4].\\n\\nFix by checking that the remote destination exists before dereferencing\\nit.\\n\\n[1]\\nBUG: kernel NULL pointer dereference, address: 0000000000000000\\n[...]\\nCPU: 4 UID: 0 PID: 365 Comm: arping Not tainted 6.17.0-rc2-virtme-g2a89cb21162c #2 PREEMPT(voluntary)\\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014\\nRIP: 0010:vxlan_xmit+0xb58/0x15f0\\n[...]\\nCall Trace:\\n \u003cTASK\u003e\\n dev_hard_start_xmit+0x5d/0x1c0\\n __dev_queue_xmit+0x246/0xfd0\\n packet_sendmsg+0x113a/0x1850\\n __sock_sendmsg+0x38/0x70\\n __sys_sendto+0x126/0x180\\n __x64_sys_sendto+0x24/0x30\\n do_syscall_64+0xa4/0x260\\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\\n\\n[2]\\n #!/bin/bash\\n\\n ip address add 192.0.2.1/32 dev lo\\n\\n ip nexthop add id 1 via 192.0.2.2 fdb\\n ip nexthop add id 10 group 1 fdb\\n\\n ip link add name vx0 up type vxlan id 10010 local 192.0.2.1 dstport 4789 proxy\\n\\n ip neigh add 192.0.2.3 lladdr 00:11:22:33:44:55 nud perm dev vx0\\n\\n bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10\\n\\n arping -b -c 1 -s 192.0.2.1 -I vx0 192.0.2.3\\n\\n[3]\\nBUG: kernel NULL pointer dereference, address: 0000000000000000\\n[...]\\nCPU: 13 UID: 0 PID: 372 Comm: ndisc6 Not tainted 6.17.0-rc2-virtmne-g6ee90cb26014 #3 PREEMPT(voluntary)\\nHardware name: QEMU Standard PC (i440FX + PIIX, 1v996), BIOS 1.17.0-4.fc41 04/01/2x014\\nRIP: 0010:vxlan_xmit+0x803/0x1600\\n[...]\\nCall Trace:\\n \u003cTASK\u003e\\n dev_hard_start_xmit+0x5d/0x1c0\\n __dev_queue_xmit+0x246/0xfd0\\n ip6_finish_output2+0x210/0x6c0\\n ip6_finish_output+0x1af/0x2b0\\n ip6_mr_output+0x92/0x3e0\\n ip6_send_skb+0x30/0x90\\n rawv6_sendmsg+0xe6e/0x12e0\\n __sock_sendmsg+0x38/0x70\\n __sys_sendto+0x126/0x180\\n __x64_sys_sendto+0x24/0x30\\n do_syscall_64+0xa4/0x260\\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\\nRIP: 0033:0x7f383422ec77\\n\\n[4]\\n #!/bin/bash\\n\\n ip address add 2001:db8:1::1/128 dev lo\\n\\n ip nexthop add id 1 via 2001:db8:1::1 fdb\\n ip nexthop add id 10 group 1 fdb\\n\\n ip link add name vx0 up type vxlan id 10010 local 2001:db8:1::1 dstport 4789 proxy\\n\\n ip neigh add 2001:db8:1::3 lladdr 00:11:22:33:44:55 nud perm dev vx0\\n\\n bridge fdb add 00:11:22:33:44:55 dev vx0 self static nhid 10\\n\\n ndisc6 -r 1 -s 2001:db8:1::1 -w 1 2001:db8:1::3 vx0\"}], \"affected\": [{\"product\": \"Linux\", \"vendor\": \"Linux\", \"defaultStatus\": \"unaffected\", \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"programFiles\": [\"drivers/net/vxlan/vxlan_core.c\"], \"versions\": [{\"version\": \"1274e1cc42264d4e629841e4f182795cb0becfd2\", \"lessThan\": \"e211e3f4199ac829bd493632efcd131d337cba9d\", \"status\": \"affected\", \"versionType\": \"git\"}, {\"version\": \"1274e1cc42264d4e629841e4f182795cb0becfd2\", \"lessThan\": \"8cfa0f076842f9b3b4eb52ae0e41d16e25cbf8fa\", \"status\": \"affected\", \"versionType\": \"git\"}, 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false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"versionStartIncluding\": \"5.8\", \"versionEndExcluding\": \"6.12.46\"}, {\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"versionStartIncluding\": \"5.8\", \"versionEndExcluding\": \"6.16.6\"}, {\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"versionStartIncluding\": \"5.8\", \"versionEndExcluding\": \"6.17\"}]}]}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/e211e3f4199ac829bd493632efcd131d337cba9d\"}, {\"url\": \"https://git.kernel.org/stable/c/8cfa0f076842f9b3b4eb52ae0e41d16e25cbf8fa\"}, {\"url\": \"https://git.kernel.org/stable/c/1f5d2fd1ca04a23c18b1bde9a43ce2fa2ffa1bce\"}], \"title\": \"vxlan: Fix NPD in {arp,neigh}_reduce() when using nexthop objects\", \"x_generator\": {\"engine\": \"bippy-1.2.0\"}}, \"adp\": [{\"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.5, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2025-39850\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-01-14T19:20:51.126279Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-476\", \"description\": \"CWE-476 NULL Pointer Dereference\"}]}], \"providerMetadata\": {\"shortName\": \"CISA-ADP\", \"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"dateUpdated\": \"2026-01-14T19:20:46.105Z\"}, \"title\": \"CISA ADP Vulnrichment\"}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2025-39850\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"state\": \"PUBLISHED\", \"assignerShortName\": \"Linux\", \"dateReserved\": \"2025-04-16T07:20:57.142Z\", \"datePublished\": \"2025-09-19T15:26:22.803Z\", \"dateUpdated\": \"2025-09-29T06:01:01.501Z\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.