{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2025-39980", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-39980", "idYear": 2025, "status": "PUBLISHED", "publishedAt": "2025-10-15T07:56:00.275Z", "updatedAt": "2026-10-15T01:08:47.582Z", "importedAt": "2026-10-24T01:57:34.152Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "nexthop: Forbid FDB status change while nexthop is in a group", "summary": "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 \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", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "38428d68719c454d269cb03b776d8a4b0ad66111", "status": "affected", "versionType": "git", "lessThan": "e1e87ac0daacd51f522ecd1645cd76b5809303ed" }, { "version": "38428d68719c454d269cb03b776d8a4b0ad66111", "status": "affected", "versionType": "git", "lessThan": "0e7bfe7a268ccbd7859730c529161cafbf44637c" }, { "version": "38428d68719c454d269cb03b776d8a4b0ad66111", "status": "affected", "versionType": "git", "lessThan": "ec428fff792b7bd15b248dafca2e654b666b1304" }, { "version": "38428d68719c454d269cb03b776d8a4b0ad66111", "status": "affected", "versionType": "git", "lessThan": "24046d31f6f92220852d393d510b6062843e3fbd" }, { "version": "38428d68719c454d269cb03b776d8a4b0ad66111", "status": "affected", "versionType": "git", "lessThan": "f0e49fd13afe9dea7a09a1c9537fd00cea22badb" }, { "version": "38428d68719c454d269cb03b776d8a4b0ad66111", "status": "affected", "versionType": "git", "lessThan": "8dd4aa0122885f710930de135af2adc4ccc3238f" }, { "version": "38428d68719c454d269cb03b776d8a4b0ad66111", "status": "affected", "versionType": "git", "lessThan": "390b3a300d7872cef9588f003b204398be69ce08" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "5.8", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "5.8" }, { "version": "5.10.245", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.194", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.155", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.109", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.50", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.16.10", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.16.*" }, { "version": "6.17", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }