{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "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": "2026-05-11T21:37:39.082Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T21:37:39.082Z" }, "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's 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 \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 \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" }, { "version": "1274e1cc42264d4e629841e4f182795cb0becfd2", "lessThan": "1f5d2fd1ca04a23c18b1bde9a43ce2fa2ffa1bce", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/vxlan/vxlan_core.c" ], "versions": [ { "version": "5.8", "status": "affected" }, { "version": "0", "lessThan": "5.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.46", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.6", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": 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" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-01-14T19:23:12.307Z" } } ] } }