N/A - CVE-2025-37921

Executive Summary

Informations
Name	CVE-2025-37921	First vendor Publication	2025-05-20
Vendor	Cve	Last vendor Modification	2025-05-21

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score	NA
Base Score	NA	Environmental Score	NA
impact SubScore	NA	Temporal Score	NA
Exploitabality Sub Score	NA

Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector :
Cvss Base Score	N/A	Attack Range	N/A
Cvss Impact Score	N/A	Attack Complexity	N/A
Cvss Expoit Score	N/A	Authentication	N/A
Calculate full CVSS 2.0 Vectors scores

Detail

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:

__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