CVE-2025-37921

High

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: <TASK> __vxlan_fdb_delete+0xbe/0x560 vxlan_vni_delete_group+0x2ba/0x940 vxlan_vni_del.isra.0+0x15f/0x580 vxlan_process_vni_filter+0x38b/0x7b0 vxlan_vnifilter_process+0x3bb/0x510 rtnetlink_rcv_msg+0x2f7/0xb70 netlink_rcv_skb+0x131/0x360 netlink_unicast+0x426/0x710 netlink_sendmsg+0x75a/0xc20 __sock_sendmsg+0xc1/0x150 ____sys_sendmsg+0x5aa/0x7b0 ___sys_sendmsg+0xfc/0x180 __sys_sendmsg+0x121/0x1b0 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x4b/0x53

Package Linux Kernel
Published 2025-05-20
Last modified 2025-11-10
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 5.18 and later are affected. Fixed in 6.1.138, 6.6.90, 6.12.28, 6.14.6, 6.15 and their respective stable series.

Affected from
≥ 5.18
Fixed in
✓ 6.1.138 6.1.x ✓ 6.6.90 6.6.x ✓ 6.12.28 6.12.x ✓ 6.14.6 6.14.x ✓ 6.15

References

The following references provide additional information about CVE-2025-37921 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

5 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2025-37921?

    CVE-2025-37921 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 5.18 onward and has been patched in 6.1.138, 6.6.90, 6.12.28 and others. CVE-2025-37921 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-37921?

    CVE-2025-37921 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2025-37921?

    Yes — CVE-2025-37921 has been patched. Fixed versions include 6.1.138, 6.6.90, 6.12.28 and others. If you are running Linux kernel 5.18 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-37921 actively exploited?

    No — CVE-2025-37921 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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