{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-05-10T06:59:44.597","vulnerabilities":[{"cve":{"id":"CVE-2025-38248","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","published":"2025-07-09T11:15:26.963","lastModified":"2026-03-17T13:32:54.233","vulnStatus":"Analyzed","cveTags":[],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: mcast: Fix use-after-free during router port configuration\n\nThe bridge maintains a global list of ports behind which a multicast\nrouter resides. The list is consulted during forwarding to ensure\nmulticast packets are forwarded to these ports even if the ports are not\nmember in the matching MDB entry.\n\nWhen per-VLAN multicast snooping is enabled, the per-port multicast\ncontext is disabled on each port and the port is removed from the global\nrouter port list:\n\n # ip link add name br1 up type bridge vlan_filtering 1 mcast_snooping 1\n # ip link add name dummy1 up master br1 type dummy\n # ip link set dev dummy1 type bridge_slave mcast_router 2\n $ bridge -d mdb show | grep router\n router ports on br1: dummy1\n # ip link set dev br1 type bridge mcast_vlan_snooping 1\n $ bridge -d mdb show | grep router\n\nHowever, the port can be re-added to the global list even when per-VLAN\nmulticast snooping is enabled:\n\n # ip link set dev dummy1 type bridge_slave mcast_router 0\n # ip link set dev dummy1 type bridge_slave mcast_router 2\n $ bridge -d mdb show | grep router\n router ports on br1: dummy1\n\nSince commit 4b30ae9adb04 (\"net: bridge: mcast: re-implement\nbr_multicast_{enable, disable}_port functions\"), when per-VLAN multicast\nsnooping is enabled, multicast disablement on a port will disable the\nper-{port, VLAN} multicast contexts and not the per-port one. As a\nresult, a port will remain in the global router port list even after it\nis deleted. This will lead to a use-after-free [1] when the list is\ntraversed (when adding a new port to the list, for example):\n\n # ip link del dev dummy1\n # ip link add name dummy2 up master br1 type dummy\n # ip link set dev dummy2 type bridge_slave mcast_router 2\n\nSimilarly, stale entries can also be found in the per-VLAN router port\nlist. When per-VLAN multicast snooping is disabled, the per-{port, VLAN}\ncontexts are disabled on each port and the port is removed from the\nper-VLAN router port list:\n\n # ip link add name br1 up type bridge vlan_filtering 1 mcast_snooping 1 mcast_vlan_snooping 1\n # ip link add name dummy1 up master br1 type dummy\n # bridge vlan add vid 2 dev dummy1\n # bridge vlan global set vid 2 dev br1 mcast_snooping 1\n # bridge vlan set vid 2 dev dummy1 mcast_router 2\n $ bridge vlan global show dev br1 vid 2 | grep router\n       router ports: dummy1\n # ip link set dev br1 type bridge mcast_vlan_snooping 0\n $ bridge vlan global show dev br1 vid 2 | grep router\n\nHowever, the port can be re-added to the per-VLAN list even when\nper-VLAN multicast snooping is disabled:\n\n # bridge vlan set vid 2 dev dummy1 mcast_router 0\n # bridge vlan set vid 2 dev dummy1 mcast_router 2\n $ bridge vlan global show dev br1 vid 2 | grep router\n       router ports: dummy1\n\nWhen the VLAN is deleted from the port, the per-{port, VLAN} multicast\ncontext will not be disabled since multicast snooping is not enabled\non the VLAN. As a result, the port will remain in the per-VLAN router\nport list even after it is no longer member in the VLAN. This will lead\nto a use-after-free [2] when the list is traversed (when adding a new\nport to the list, for example):\n\n # ip link add name dummy2 up master br1 type dummy\n # bridge vlan add vid 2 dev dummy2\n # bridge vlan del vid 2 dev dummy1\n # bridge vlan set vid 2 dev dummy2 mcast_router 2\n\nFix these issues by removing the port from the relevant (global or\nper-VLAN) router port list in br_multicast_port_ctx_deinit(). The\nfunction is invoked during port deletion with the per-port multicast\ncontext and during VLAN deletion with the per-{port, VLAN} multicast\ncontext.\n\nNote that deleting the multicast router timer is not enough as it only\ntakes care of the temporary multicast router states (1 or 3) and not the\npermanent one (2).\n\n[1]\nBUG: KASAN: slab-out-of-bounds in br_multicast_add_router.part.0+0x3f1/0x560\nWrite of size 8 at addr ffff888004a67328 by task ip/384\n[...]\nCall Trace:\n <TASK>\n dump_stack\n---truncated---"},{"lang":"es","value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bridge: mcast: Arreglar el use-after-free durante la configuración del puerto del enrutador El puente mantiene una lista global de puertos tras los cuales reside un enrutador de multidifusión. La lista se consulta durante el reenvío para garantizar que los paquetes de multidifusión se reenvíen a estos puertos incluso si los puertos no son miembros de la entrada MDB correspondiente. Cuando se habilita la vigilancia de multidifusión por VLAN, se deshabilita el contexto de multidifusión por puerto en cada puerto y el puerto se elimina de la lista global de puertos del enrutador: # ip link add name br1 up type bridge vlan_filtering 1 mcast_snooping 1 # ip link add name dummy1 up master br1 type dummy # ip link set dev dummy1 type bridge_slave mcast_router 2 $ bridge -d mdb show | grep router router ports on br1: dummy1 # ip link set dev br1 type bridge mcast_vlan_snooping 1 $ bridge -d mdb show | grep router Sin embargo, el puerto se puede volver a agregar a la lista global incluso cuando el snooping de multidifusión por VLAN está habilitado: # ip link set dev dummy1 type bridge_slave mcast_router 0 # ip link set dev dummy1 type bridge_slave mcast_router 2 $ bridge -d mdb show | grep router router ports on br1: dummy1 Desde el commit 4b30ae9adb04 (\"net: bridge: mcast: re-implement br_multicast_{enable, disabled}_port functions\"), cuando el snooping de multidifusión por VLAN está habilitado, la deshabilitación de multidifusión en un puerto deshabilitará los contextos de multidifusión por {puerto, VLAN} y no el de cada puerto. Como resultado, un puerto permanecerá en la lista global de puertos del enrutador incluso después de eliminarlo. Esto generará un use-after-free [1] cuando se recorra la lista (al agregar un nuevo puerto a la lista, por ejemplo): # ip link del dev dummy1 # ip link add name dummy2 up master br1 type dummy # ip link set dev dummy2 type bridge_slave mcast_router 2 De manera similar, también se pueden encontrar entradas obsoletas en la lista de puertos del enrutador por VLAN. Cuando la vigilancia de multidifusión por VLAN está deshabilitada, los contextos por {puerto, VLAN} se deshabilitan en cada puerto y el puerto se elimina de la lista de puertos del enrutador por VLAN: # ip link add name br1 up type bridge vlan_filtering 1 mcast_snooping 1 mcast_vlan_snooping 1 # ip link add name dummy1 up master br1 type dummy # bridge vlan add vid 2 dev dummy1 # bridge vlan global set vid 2 dev br1 mcast_snooping 1 # bridge vlan set vid 2 dev dummy1 mcast_router 2 $ bridge vlan global show dev br1 vid 2 | grep router router ports: dummy1 # ip link set dev br1 type bridge mcast_vlan_snooping 0 $ bridge vlan global show dev br1 vid 2 | grep router Sin embargo, el puerto se puede volver a agregar a la lista por VLAN incluso cuando el snooping de multidifusión por VLAN está deshabilitado: # bridge vlan set vid 2 dev dummy1 mcast_router 0 # bridge vlan set vid 2 dev dummy1 mcast_router 2 $ bridge vlan global show dev br1 vid 2 | grep router router ports: dummy1 Cuando se elimina la VLAN del puerto, el contexto de multidifusión por {puerto, VLAN} no se deshabilitará ya que el snooping de multidifusión no está habilitado en la VLAN. Como resultado, el puerto permanecerá en la lista de puertos del enrutador por VLAN incluso después de que ya no sea miembro de la VLAN. Esto dará lugar a un use-after-free [2] cuando se recorra la lista (al añadir un nuevo puerto a la lista, por ejemplo): # ip link add name dummy2 up master br1 type dummy # bridge vlan add vid 2 dev dummy2 # bridge vlan del vid 2 dev dummy1 # bridge vlan set vid 2 dev dummy2 mcast_router 2 Solucione estos problemas eliminando el puerto de la lista de puertos del enrutador relevante (global o por VLAN) en br_multicast_port_ctx_deinit(). La función se invoca durante la eliminación del puerto con el contexto de multidifusión por puerto y durante la eliminación de VLAN con el contexto de multidifusión por {puerto, VLAN}. ---truncado---"}],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"weaknesses":[{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"CWE-416"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.15.5","matchCriteriaId":"F39C8291-E4C4-42A0-BA95-5A123ED5CAF4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:*","matchCriteriaId":"6D4894DB-CCFE-4602-B1BF-3960B2E19A01"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.16:rc2:*:*:*:*:*:*","matchCriteriaId":"09709862-E348-4378-8632-5A7813EDDC86"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.16:rc3:*:*:*:*:*:*","matchCriteriaId":"415BF58A-8197-43F5-B3D7-D1D63057A26E"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/4d3c2a1d4c7c33103f1ddfdbc5cfe1ea4f6d0dcd","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/7544f3f5b0b58c396f374d060898b5939da31709","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/bdced577da71b118b6ed4242ebd47f81bf54d406","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/f05a4f9e959e0fc098046044c650acf897ea52d2","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]}]}}]}