CVE-2025-71097
BaseFortify
Publication date: 2026-01-13
Last updated on: 2026-03-25
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | 5.3 |
| linux | linux_kernel | From 5.11 (inc) to 5.15.198 (exc) |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | From 6.13 (inc) to 6.18.4 (exc) |
| linux | linux_kernel | From 5.16 (inc) to 6.1.160 (exc) |
| linux | linux_kernel | From 6.2 (inc) to 6.6.120 (exc) |
| linux | linux_kernel | From 6.7 (inc) to 6.12.64 (exc) |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | 6.19 |
| linux | linux_kernel | From 5.3.1 (inc) to 5.10.248 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a reference count leak in the Linux kernel's IPv4 networking code. When a nexthop object is deleted, it is marked as dead, and the system is supposed to flush all routes using that nexthop. However, the existing logic only flushes error routes (like blackhole routes) during network namespace dismantle, not when the nexthop is deleted. As a result, error routes continue to hold references to the deleted nexthop object and its device, causing a reference count leak that prevents the device from being freed properly. This issue does not affect IPv6.
How can this vulnerability impact me? :
This vulnerability can cause resource leaks in the Linux kernel networking stack by preventing network devices associated with deleted nexthop objects from being freed. This can lead to increased memory usage and potentially degrade system performance or stability over time, especially in environments where nexthop objects and error routes are frequently created and deleted.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by checking for lingering error routes (such as blackhole routes) that still reference deleted nexthop objects. You can use the following commands to detect this condition: # ip link add name dummy1 up type dummy # ip nexthop add id 1 dev dummy1 # ip route add 198.51.100.1/32 nhid 1 # ip route add blackhole 198.51.100.2/32 nhid 1 # ip nexthop del id 1 # ip route show If you see blackhole routes still referencing the deleted nexthop (nhid 1), it indicates the reference count leak vulnerability is present. Also, attempting to delete the device with 'ip link del dev dummy1' may hang or show usage count warnings, indicating the leak.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, ensure that your Linux kernel is updated with the fix that flushes error routes when their nexthop is marked as dead. This prevents the reference count leak. Until the fix is applied, avoid deleting nexthop objects that are still referenced by error routes, or manually flush such routes before deleting nexthops.