Linux Kernel up to 6.17.8 ipv4 rt_bind_exception reference count

CVSS Meta Temp Score
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CTI Interest Score
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4.6$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.17.8. This impacts the function rt_bind_exception of the component ipv4. The manipulation leads to reference count. This vulnerability is referenced as CVE-2025-68241. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.17.8 and classified as critical. This issue affects the function rt_bind_exception of the component ipv4. The manipulation with an unknown input leads to a reference count vulnerability. Using CWE to declare the problem leads to CWE-911. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ipv4: route: Prevent rt_bind_exception() from rebinding stale fnhe The sit driver's packet transmission path calls: sit_tunnel_xmit() -> update_or_create_fnhe(), which lead to fnhe_remove_oldest() being called to delete entries exceeding FNHE_RECLAIM_DEPTH+random. The race window is between fnhe_remove_oldest() selecting fnheX for deletion and the subsequent kfree_rcu(). During this time, the concurrent path's __mkroute_output() -> find_exception() can fetch the soon-to-be-deleted fnheX, and rt_bind_exception() then binds it with a new dst using a dst_hold(). When the original fnheX is freed via RCU, the dst reference remains permanently leaked. CPU 0 CPU 1 __mkroute_output() find_exception() [fnheX] update_or_create_fnhe() fnhe_remove_oldest() [fnheX] rt_bind_exception() [bind dst] RCU callback [fnheX freed, dst leak] This issue manifests as a device reference count leak and a warning in dmesg when unregistering the net device: unregister_netdevice: waiting for sitX to become free. Usage count = N Ido Schimmel provided the simple test validation method [1]. The fix clears 'oldest->fnhe_daddr' before calling fnhe_flush_routes(). Since rt_bind_exception() checks this field, setting it to zero prevents the stale fnhe from being reused and bound to a new dst just before it is freed. [1] ip netns add ns1 ip -n ns1 link set dev lo up ip -n ns1 address add 192.0.2.1/32 dev lo ip -n ns1 link add name dummy1 up type dummy ip -n ns1 route add 192.0.2.2/32 dev dummy1 ip -n ns1 link add name gretap1 up arp off type gretap \ local 192.0.2.1 remote 192.0.2.2 ip -n ns1 route add 198.51.0.0/16 dev gretap1 taskset -c 0 ip netns exec ns1 mausezahn gretap1 \ -A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q & taskset -c 2 ip netns exec ns1 mausezahn gretap1 \ -A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q & sleep 10 ip netns pids ns1 | xargs kill ip netns del ns1

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2025-68241 since 12/16/2025. The exploitation is known to be difficult. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 282382 (Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1350)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.302, 5.10.247, 5.15.197, 6.1.159, 6.6.117, 6.12.59 or 6.17.9 eliminates this vulnerability. Applying the patch 69d35c12168f9c59b159ae566f77dfad9f96d7ca/4b7210da22429765d19460d38c30eeca72656282/298f1e0694ab4edb6092d66efed93c4554e6ced1/b8a44407bdaf2f0c5505cc7d9fc7d8da90cf9a94/041ab9ca6e80d8f792bb69df28ebf1ef39c06af8/b84f083f50ecc736a95091691339a1b363962f0e/0fd16ed6dc331636fb2a874c42d2f7d3156f7ff0/ac1499fcd40fe06479e9b933347b837ccabc2a40 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (282382) and CERT Bund (WID-SEC-2025-2868). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.6

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Reference count
CWE: CWE-911 / CWE-664
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 282382
Nessus Name: Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2025-1350)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.4.302/5.10.247/5.15.197/6.1.159/6.6.117/6.12.59/6.17.9
Patch: 69d35c12168f9c59b159ae566f77dfad9f96d7ca/4b7210da22429765d19460d38c30eeca72656282/298f1e0694ab4edb6092d66efed93c4554e6ced1/b8a44407bdaf2f0c5505cc7d9fc7d8da90cf9a94/041ab9ca6e80d8f792bb69df28ebf1ef39c06af8/b84f083f50ecc736a95091691339a1b363962f0e/0fd16ed6dc331636fb2a874c42d2f7d3156f7ff0/ac1499fcd40fe06479e9b933347b837ccabc2a40

Timelineinfo

12/16/2025 Advisory disclosed
12/16/2025 +0 days CVE reserved
12/16/2025 +0 days VulDB entry created
02/21/2026 +67 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-68241 (🔒)
GCVE (CVE): GCVE-0-2025-68241
GCVE (VulDB): GCVE-100-336785
CERT Bund: WID-SEC-2025-2868 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 12/16/2025 16:05
Updated: 02/21/2026 23:02
Changes: 12/16/2025 16:05 (59), 01/09/2026 08:57 (2), 01/20/2026 02:09 (7), 02/03/2026 13:02 (1), 02/21/2026 23:02 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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