Bug 2373506 (CVE-2022-50043)

Summary: CVE-2022-50043 kernel: net: fix potential refcount leak in ndisc_router_discovery()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: high    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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OS: Linux   
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Description OSIDB Bzimport 2025-06-18 12:05:59 UTC 
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.
Comment 1 Avinash Hanwate 2025-06-19 20:49:41 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025061843-CVE-2022-50043-e7dc@gregkh/T