In the Linux kernel, the following vulnerability has been resolved: ipv4: route: Prevent rt_bind_exception() from rebinding stale fnhe The sit… (CVE-2025-68241)
A vulnerability in the Linux kernel's IPv4 routing code involving the sit driver was resolved. The issue allowed a race condition where a stale forwarding nexthop entry (fnhe) could be rebound to a new destination, causing a device reference count leak and warnings during network device unregistration. The fix involves clearing a field to prevent reuse of stale entries before they are freed.
AI Analysis
Technical Summary
The Linux kernel vulnerability (CVE-2025-68241) involves the sit driver's packet transmission path where a race condition between fnhe_remove_oldest() and concurrent routing functions allows rt_bind_exception() to rebind a stale forwarding nexthop entry (fnheX) to a new destination. This leads to a permanent leak of a device reference count, causing warnings such as 'unregister_netdevice: waiting for sitX to become free. Usage count = N' during net device unregistration. The fix clears the 'oldest->fnhe_daddr' field before flushing routes, preventing stale fnhe entries from being rebound and leaked.
Potential Impact
This vulnerability causes a device reference count leak in the Linux kernel networking stack, which can lead to resource exhaustion or delays in network device unregistration. The CVSS vector indicates no confidentiality or integrity impact but a high availability impact due to resource leakage.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The described fix involves clearing the 'oldest->fnhe_daddr' field before route flushing to prevent reuse of stale entries. Users should monitor vendor advisories for official patches or backported fixes and apply them once available.
In the Linux kernel, the following vulnerability has been resolved: ipv4: route: Prevent rt_bind_exception() from rebinding stale fnhe The sit… (CVE-2025-68241)
Description
A vulnerability in the Linux kernel's IPv4 routing code involving the sit driver was resolved. The issue allowed a race condition where a stale forwarding nexthop entry (fnhe) could be rebound to a new destination, causing a device reference count leak and warnings during network device unregistration. The fix involves clearing a field to prevent reuse of stale entries before they are freed.
CVSS v3.1
Score 7.5high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel vulnerability (CVE-2025-68241) involves the sit driver's packet transmission path where a race condition between fnhe_remove_oldest() and concurrent routing functions allows rt_bind_exception() to rebind a stale forwarding nexthop entry (fnheX) to a new destination. This leads to a permanent leak of a device reference count, causing warnings such as 'unregister_netdevice: waiting for sitX to become free. Usage count = N' during net device unregistration. The fix clears the 'oldest->fnhe_daddr' field before flushing routes, preventing stale fnhe entries from being rebound and leaked.
Potential Impact
This vulnerability causes a device reference count leak in the Linux kernel networking stack, which can lead to resource exhaustion or delays in network device unregistration. The CVSS vector indicates no confidentiality or integrity impact but a high availability impact due to resource leakage.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The described fix involves clearing the 'oldest->fnhe_daddr' field before route flushing to prevent reuse of stale entries. Users should monitor vendor advisories for official patches or backported fixes and apply them once available.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-vwj6-rppm-qjrp
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2025-68241"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a6b72d39c2644c7f8477fff
Added to database: 07/30/2026, 15:50:43 UTC
Last enriched: 07/30/2026, 18:40:40 UTC
Last updated: 09/10/2026, 19:38:48 UTC
Views: 12
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