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CVE-2025-71097· NVD / CVE Program· CNA Linux

ipv4: Fix reference count leak when using error routes with nexthop objects

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.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jan 13, 2026
Updated
Sep 8, 2026
EPSS
0.1% · 2th percentile
CWE
—
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Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Affected systems

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.3.1 and later · before 5.10.248
  • linux linux kernel5.11 and later · before 5.15.198
  • linux linux kernel5.16 and later · before 6.1.160
  • linux linux kernel6.2 and later · before 6.6.120
  • linux linux kernel6.7 and later · before 6.12.64
  • linux linux kernel6.13 and later · before 6.18.4
  • linux linux kernel5.3
  • linux linux kernel6.19

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.3affected
    • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e and later · before 5de7ad7e18356e39e8fbf7edd185a5faaf4f385aaffected · git
    • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e and later · before 33ff5c207c873215e54e6176624ed57423cb7deaaffected · git
    • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e and later · before 30386e090c49e803c0616a7147e43409c32a2b0eaffected · git
    • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e and later · before 5979338c83012110ccd45cae6517591770bfe536affected · git
    • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e and later · before ee4183501ea556dca31f5ffd8690aa9fd25b609faffected · git
    • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e and later · before e3fc381320d04e4a74311e576a86cac49a16fc43affected · git
    • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e and later · before ac782f4e3bfcde145b8a7f8af31d9422d94d172aaffected · git
    • before 5.3not affected · semver
    • 5.10.248 and later · up to and including 5.10.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.162-16.1.162-1
Debian:13linuxbefore 6.12.69-16.12.69-1
Debian:14linuxbefore 6.18.5-16.18.5-1

Same product

linux: all records

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux30386e090c49e803c0616a7147e43409c32a2b0eVendor (CNA)
Linux Linux33ff5c207c873215e54e6176624ed57423cb7deaVendor (CNA)
Linux Linux5979338c83012110ccd45cae6517591770bfe536Vendor (CNA)
Linux Linux5de7ad7e18356e39e8fbf7edd185a5faaf4f385aVendor (CNA)
Linux Linuxac782f4e3bfcde145b8a7f8af31d9422d94d172aVendor (CNA)
Linux Linuxe3fc381320d04e4a74311e576a86cac49a16fc43Vendor (CNA)
Linux Linuxee4183501ea556dca31f5ffd8690aa9fd25b609fVendor (CNA)
Debian:linux6.1.162-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records