CVE-2025-37921
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
Leer descripción completaMostrar menos
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.
Detalles técnicos trazas, registros y código del informe original
[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
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 7.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 10
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation75 % - Impacto principal
T1499.004Application or System Exploitationimpact65 %
AV:L + PR:L sin UI indica escalada local. La falta de sincronización (race condition) en eliminación de FDB puede causar DoS por corrupción de memoria o crash del kernel.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (2)
CWE
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/087a9eb9e5978e3ba362e1163691e41097e8ca20
- https://git.kernel.org/stable/c/2d4a121296aa3940d2df9906f955c2b6b4e38bc3
- https://git.kernel.org/stable/c/3576e9a80b6c4381b01ce0cbaa07f5e92d4492ed
- https://git.kernel.org/stable/c/470206205588559e60035fceb5f256640cb45f99
- https://git.kernel.org/stable/c/5cb9e07f84e527974b12e82e2549fa6c0cc6eef0
- https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: vnifilter: Fix unlocked deletion of default FDB entry\n\nWhen a VNI is deleted from a VXLAN device in 'vnifilter' mode, the FDB\nentry associated with the default remote (assuming one was configured)\nis deleted without holding the hash lock. This is wrong and will result\nin a warning [1] being generated by the lockdep annotation that was\nadded by commit ebe642067455 (\"vxlan: Create wrappers for FDB lookup\").\n\nReproducer:\n\n # ip link add vx0 up type vxlan dstport 4789 external vnifilter local 192.0.2.1\n # bridge vni add vni 10010 remote 198.51.100.1 dev vx0\n # bridge vni del vni 10010 dev vx0\n\nFix by acquiring the hash lock before the deletion and releasing it\nafterwards. Blame the original commit that introduced the issue rather\nthan the one that exposed it.\n\n[1]\nWARNING: CPU: 3 PID: 392 at drivers/net/vxlan/vxlan_core.c:417 vxlan_find_mac+0x17f/0x1a0\n[...]\nRIP: 0010:vxlan_find_mac+0x17f/0x1a0\n[...]\nCall Trace:\n <TASK>\n __vxlan_fdb_delete+0xbe/0x560\n vxlan_vni_delete_group+0x2ba/0x940\n vxlan_vni_del.isra.0+0x15f/0x580\n vxlan_process_vni_filter+0x38b/0x7b0\n vxlan_vnifilter_process+0x3bb/0x510\n rtnetlink_rcv_msg+0x2f7/0xb70\n netlink_rcv_skb+0x131/0x360\n netlink_unicast+0x426/0x710\n netlink_sendmsg+0x75a/0xc20\n __sock_sendmsg+0xc1/0x150\n ____sys_sendmsg+0x5aa/0x7b0\n ___sys_sendmsg+0xfc/0x180\n __sys_sendmsg+0x121/0x1b0\n do_syscall_64+0xbb/0x1d0\n entry_SYSCALL_64_after_hwframe+0x4b/0x53"
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"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: vxlan: vnifilter: Se corrige la eliminación desbloqueada de la entrada FDB predeterminada. Cuando se elimina una VNI de un dispositivo VXLAN en modo 'vnifilter', la entrada FDB asociada al control remoto predeterminado (si se configuró uno) se elimina sin mantener el bloqueo hash. Esto es incorrecto y generará una advertencia [1] generada por la anotación lockdep, añadida por el commit ebe642067455 (\"vxlan: Crear envoltorios para la búsqueda FDB\"). Reproductor: # 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 Se corrige adquiriendo el bloqueo hash antes de la eliminación y liberándolo después. Culpe a el commit original que introdujo el problema en lugar de a la que lo expuso. [1] ADVERTENCIA: CPU: 3 PID: 392 en drivers/net/vxlan/vxlan_core.c:417 vxlan_find_mac+0x17f/0x1a0 [...] RIP: 0010:vxlan_find_mac+0x17f/0x1a0 [...] Rastreo de llamadas: __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 "
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