net: nexthop: fix percpu use-after-free in remove_nh_grp_entry
In the Linux kernel, the following vulnerability has been resolved: net: nexthop: fix percpu use-after-free in remove_nh_grp_entry When removing a nexthop from a group, remove_nh_grp_entry() publishes the new group via rcu_assign_pointer() then immediately frees the removed entry's percpu stats with free_percpu(). However, the synchronize_net() grace period in the caller remove_nexthop_from_groups() runs after the free. RCU readers that entered before the publish still see the old group and can dereference the freed stats via nh_grp_entry_stats_inc() -> get_cpu_ptr(nhge->stats), causing a use-after-free on percpu memory. Fix by deferring the free_percpu() until after synchronize_net() in the caller. Removed entries are chained via nh_list onto a local deferred free list. After the grace period completes and all RCU readers have finished, the percpu stats are safely freed.
CVE-2026-43374
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-2026-43374
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": "f4676ea74b8549cd88dbfe2a592ce4530039e61f",
"lessThan": "abf4feaee6405f1441929c6ebe7a250f2cd170a7",
"versionType": "git"
},
{
"status": "affected",
"version": "f4676ea74b8549cd88dbfe2a592ce4530039e61f",
"lessThan": "ab5ebab9664214ba41a7633cb4e72f128204f924",
"versionType": "git"
},
{
"status": "affected",
"version": "f4676ea74b8549cd88dbfe2a592ce4530039e61f",
"lessThan": "9e08ad731862b22a87cc55f752e16d66cdc9e231",
"versionType": "git"
},
{
"status": "affected",
"version": "f4676ea74b8549cd88dbfe2a592ce4530039e61f",
"lessThan": "b2662e7593e94ae09b1cf7ee5f09160a3612bcb2",
"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": "6.9"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.9",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.78",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.19",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.9",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ipv4/nexthop.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-43374
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40069 · Revision 1
- Added to Heist Feed
- Publisher date