CVE-2025-71097

Medium

In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix reference count leak when using error routes with nexthop objects When a nexthop object is deleted, it is marked as dead and then fib_table_flush() is called to flush all the routes that are using the dead nexthop. The current logic in fib_table_flush() is to only flush error routes (e.g., blackhole) when it is called as part of network namespace dismantle (i.e., with flush_all=true). Therefore, error routes are not flushed when their nexthop object is deleted: # 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 blackhole 198.51.100.2 nhid 1 dev dummy1 As such, they keep holding a reference on the nexthop object which in turn holds a reference on the nexthop device, resulting in a reference count leak: # ip link del dev dummy1 [ 70.516258] unregister_netdevice: waiting for dummy1 to become free. Usage count = 2 Fix by flushing error routes when their nexthop is marked as dead. IPv6 does not suffer from this problem.

Package Linux Kernel
Published 2026-01-13
Last modified 2026-03-25
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 5.3 and later are affected. Fixed in 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.4, 6.19 and their respective stable series.

Affected from
≥ 5.3
Fixed in
✓ 5.10.248 5.10.x ✓ 5.15.198 5.15.x ✓ 6.1.160 6.1.x ✓ 6.6.120 6.6.x ✓ 6.12.64 6.12.x ✓ 6.18.4 6.18.x ✓ 6.19

References

The following references provide additional information about CVE-2025-71097 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

7 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2025-71097?

    CVE-2025-71097 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 5.3 onward and has been patched in 5.10.248, 5.15.198, 6.1.160 and others. CVE-2025-71097 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-71097?

    CVE-2025-71097 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2025-71097?

    Yes — CVE-2025-71097 has been patched. Fixed versions include 5.10.248, 5.15.198, 6.1.160 and others. If you are running Linux kernel 5.3 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-71097 actively exploited?

    No — CVE-2025-71097 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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