CVE-2025-37921
7.8 · HIGHOverview
CVE-2025-37921 is a high-severity vulnerability affecting linux linux_kernel. It was published on May 20, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
vxlan: vnifilter: Fix unlocked deletion of default FDB entry
When a VNI is deleted from a VXLAN device in 'vnifilter' mode, the FDB
entry associated with the default remote (assuming one was configured)
is deleted without holding the hash lock. This is wrong and will result
in a warning [1] being generated by the lockdep annotation that was
added by commit ebe642067455 ("vxlan: Create wrappers for FDB lookup").
Reproducer:
# ip link add vx0 up type vxlan dstport 4789 external vnifilter local 192.0.2.1
# bridge vni add vni 10010 remote 198.51.100.1 dev vx0
# bridge vni del vni 10010 dev vx0
Fix by acquiring the hash lock before the deletion and releasing it
afterwards. Blame the original commit that introduced the issue rather
than the one that exposed it.
[1]
WARNING: CPU: 3 PID: 392 at drivers/net/vxlan/vxlan_core.c:417 vxlan_find_mac+0x17f/0x1a0
[...]
RIP: 0010:vxlan_find_mac+0x17f/0x1a0
[...]
Call Trace:
<
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 5.18, < 6.1.138 | Affected |
References
Frequently Asked Questions
What is CVE-2025-37921?
CVE-2025-37921 is a high-severity vulnerability affecting linux linux_kernel. It was published on May 20, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).
How severe is CVE-2025-37921?
This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2025-37921?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-37921?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-37921 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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