nexthop: Forbid FDB status change while nexthop is in a group
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:f
CVE-2025-39980
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2025-39980
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "38428d68719c454d269cb03b776d8a4b0ad66111",
"lessThan": "e1e87ac0daacd51f522ecd1645cd76b5809303ed",
"versionType": "git"
},
{
"status": "affected",
"version": "38428d68719c454d269cb03b776d8a4b0ad66111",
"lessThan": "0e7bfe7a268ccbd7859730c529161cafbf44637c",
"versionType": "git"
},
{
"status": "affected",
"version": "38428d68719c454d269cb03b776d8a4b0ad66111",
"lessThan": "ec428fff792b7bd15b248dafca2e654b666b1304",
"versionType": "git"
},
{
"status": "affected",
"version": "38428d68719c454d269cb03b776d8a4b0ad66111",
"lessThan": "24046d31f6f92220852d393d510b6062843e3fbd",
"versionType": "git"
},
{
"status": "affected",
"version": "38428d68719c454d269cb03b776d8a4b0ad66111",
"lessThan": "f0e49fd13afe9dea7a09a1c9537fd00cea22badb",
"versionType": "git"
},
{
"status": "affected",
"version": "38428d68719c454d269cb03b776d8a4b0ad66111",
"lessThan": "8dd4aa0122885f710930de135af2adc4ccc3238f",
"versionType": "git"
},
{
"status": "affected",
"version": "38428d68719c454d269cb03b776d8a4b0ad66111",
"lessThan": "390b3a300d7872cef9588f003b204398be69ce08",
"versionType": "git"
}
],
"programFiles": [
"net/ipv4/nexthop.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.245",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.194",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.155",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.109",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.50",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.16.10",
"versionType": "semver",
"lessThanOrEqual": "6.16.*"
},
{
"status": "unaffected",
"version": "6.17",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ipv4/nexthop.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-39980
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #27078 · Revision 1
- Added to Heist Feed
- Publisher date