In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix use-after-free due to MST port state bypass syzbot reported[1]… (CVE-2025-40297)
A use-after-free vulnerability in the Linux kernel's network bridge code was resolved. The issue arises from a race condition during deletion of an expired forwarding database (fdb) entry when MST (Multiple Spanning Tree) is enabled and VLAN filtering is disabled. This condition allows bypassing the port's disabled state, causing fdb learning to occur improperly while the port is being deleted. The fix involves adding a check on the port's VLAN group pointer to prevent this bypass. The vulnerability has a high severity rating based on CVSS 3.1 metrics.
AI Analysis
Technical Summary
CVE-2025-40297 is a use-after-free vulnerability in the Linux kernel's bridge networking component. It occurs due to a race condition between ongoing fdb learning and port deletion when MST is enabled and VLAN filtering is disabled. The port's state is toggled to disabled during deletion to prevent learning, but MST bypasses this state, allowing learning to continue on a port being deleted, leading to use-after-free. The patch adds a check on the port's vlan group pointer, which is set to NULL during deletion, preventing the bypass and eliminating the race condition.
Potential Impact
Successful exploitation could lead to memory corruption via use-after-free, potentially allowing an attacker with local access to cause denial of service or escalate privileges due to corrupted kernel memory. The CVSS 3.1 vector indicates low attack complexity and privileges required, with high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
A fix for this vulnerability has been implemented in the Linux kernel. Users and administrators should apply the official kernel updates that include this patch once available. Patch status is not yet confirmed in this data; check the Linux kernel vendor advisory for current remediation guidance.
In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix use-after-free due to MST port state bypass syzbot reported[1]… (CVE-2025-40297)
Description
A use-after-free vulnerability in the Linux kernel's network bridge code was resolved. The issue arises from a race condition during deletion of an expired forwarding database (fdb) entry when MST (Multiple Spanning Tree) is enabled and VLAN filtering is disabled. This condition allows bypassing the port's disabled state, causing fdb learning to occur improperly while the port is being deleted. The fix involves adding a check on the port's VLAN group pointer to prevent this bypass. The vulnerability has a high severity rating based on CVSS 3.1 metrics.
CVSS v3.1
Score 7.8high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2025-40297 is a use-after-free vulnerability in the Linux kernel's bridge networking component. It occurs due to a race condition between ongoing fdb learning and port deletion when MST is enabled and VLAN filtering is disabled. The port's state is toggled to disabled during deletion to prevent learning, but MST bypasses this state, allowing learning to continue on a port being deleted, leading to use-after-free. The patch adds a check on the port's vlan group pointer, which is set to NULL during deletion, preventing the bypass and eliminating the race condition.
Potential Impact
Successful exploitation could lead to memory corruption via use-after-free, potentially allowing an attacker with local access to cause denial of service or escalate privileges due to corrupted kernel memory. The CVSS 3.1 vector indicates low attack complexity and privileges required, with high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
A fix for this vulnerability has been implemented in the Linux kernel. Users and administrators should apply the official kernel updates that include this patch once available. Patch status is not yet confirmed in this data; check the Linux kernel vendor advisory for current remediation guidance.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-9jpf-8hq9-w5f5
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2025-40297"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a6b72d49c2644c7f847925a
Added to database: 07/30/2026, 15:50:44 UTC
Last enriched: 07/30/2026, 17:52:10 UTC
Last updated: 09/10/2026, 19:38:45 UTC
Views: 11
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