CVE-2022-50043: net: fix potential refcount leak in ndisc_router_discovery()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-06-18 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: net: fix potential refcount leak in ndisc_router_discovery() The issue happens on specific paths in the function. After both the object `rt` and `neigh` are grabbed successfully, when `lifetime` is nonzero but the metric needs change, the function just deletes the route and set `rt` to NULL. Then, it may try grabbing `rt` and `neigh` again if above conditions hold. The function simply overwrite `neigh` if succeeds or returns if fails, without decreasing the reference count of previous `neigh`. This may result in memory leaks. Fix it by decrementing the reference count of `neigh` in place.

Affected products

Linux kernel: from 5.12 before 5.15.63; from 5.16 before 5.19.4; 6.0-rc1 — fixed in 5.15.63, 5.19.4

How to fix

Upgrade to a fixed version: Linux kernel 5.15.63, 5.19.4. Check the vendor advisory for mitigations.

References

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