IM
IronMonkey Threat Research

CVE-2026-23095 HIGH

Published: 2026-02-04 | Last Modified: 2026-07-14 | Status: Modified

Description

In the Linux kernel, the following vulnerability has been resolved: gue: Fix skb memleak with inner IP protocol 0. syzbot reported skb memleak below. [0] The repro generated a GUE packet with its inner protocol 0. gue_udp_recv() returns -guehdr->proto_ctype for "resubmit" in ip_protocol_deliver_rcu(), but this only works with non-zero protocol number. Let's drop such packets. Note that 0 is a valid number (IPv6 Hop-by-Hop Option). I think it is not practical to encap HOPOPT in GUE, so once someone starts to complain, we could pass down a resubmit flag pointer to distinguish two zeros from the upper layer: * no error * resubmit HOPOPT [0] BUG: memory leak unreferenced object 0xffff888109695a00 (size 240): comm "syz.0.17", pid 6088, jiffies 4294943096 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00 .@.............. backtrace (crc a84b336f): kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline] slab_post_alloc_hook mm/slub.c:4958 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270 __build_skb+0x23/0x60 net/core/skbuff.c:474 build_skb+0x20/0x190 net/core/skbuff.c:490 __tun_build_skb drivers/net/tun.c:1541 [inline] tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636 tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770 tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x45d/0x710 fs/read_write.c:686 ksys_write+0xa7/0x170 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Additional Descriptions (1)

En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta: gue: Corrige la fuga de memoria de skb con el protocolo IP interno 0. syzbot informó de una fuga de memoria de skb a continuación. [0] La reproducción generó un paquete GUE con su protocolo interno 0. gue_udp_recv() devuelve -guehdr->proto_ctype para 'resubmit' en ip_protocol_deliver_rcu(), pero esto solo funciona con números de protocolo distintos de cero. Descartemos tales paquetes. Tenga en cuenta que 0 es un número válido (Opción Salto a Salto de IPv6). Creo que no es práctico encapsular HOPOPT en GUE, así que una vez que alguien empiece a quejarse, podríamos pasar un puntero de bandera de reenvío para distinguir dos ceros de la capa superior: * sin error * reenviar HOPOPT [0] BUG: fuga de memoria objeto sin referencia 0xffff888109695a00 (tamaño 240): comm 'syz.0.17', pid 6088, jiffies 4294943096 volcado hexadecimal (primeros 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 40 c2 10 81 88 ff ff 00 00 00 00 00 00 00 00 .@.............. rastreo (crc a84b336f): kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline] slab_post_alloc_hook mm/slub.c:4958 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x3b4/0x590 mm/slub.c:5270 __build_skb+0x23/0x60 net/core/skbuff.c:474 build_skb+0x20/0x190 net/core/skbuff.c:490 __tun_build_skb drivers/net/tun.c:1541 [inline] tun_build_skb+0x4a1/0xa40 drivers/net/tun.c:1636 tun_get_user+0xc12/0x2030 drivers/net/tun.c:1770 tun_chr_write_iter+0x71/0x120 drivers/net/tun.c:1999 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x45d/0x710 fs/read_write.c:686 ksys_write+0xa7/0x170 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xa4/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CVSS Metrics

Base Score: 5.5 (MEDIUM)

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack VectorLOCAL
Attack ComplexityLOW
Privileges RequiredLOW
User InteractionNONE
ScopeUNCHANGED
Confidentiality ImpactNONE
Integrity ImpactNONE
Availability ImpactHIGH

Source: [email protected]

Type: Primary

Exploitability Score: 1.8

Impact Score: 3.6

Weaknesses

Source Type Description
[email protected] Primary
en CWE-401

Affected Products

Vendor Product Version Update Type
linux linux_kernel * <built-in method update of dict object at 0x702bdcf69e40> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdd1c9780> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdcf6a680> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdcf6b4c0> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdcf6a480> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdcf6ac00> Operating System
linux linux_kernel 6.19 <built-in method update of dict object at 0x702bdcf6a8c0> Operating System
linux linux_kernel 6.19 <built-in method update of dict object at 0x702c043d21c0> Operating System
linux linux_kernel 6.19 <built-in method update of dict object at 0x702bdc447040> Operating System
linux linux_kernel 6.19 <built-in method update of dict object at 0x702bdcf685c0> Operating System
linux linux_kernel 6.19 <built-in method update of dict object at 0x702bdd31a5c0> Operating System
linux linux_kernel 6.19 <built-in method update of dict object at 0x702bdcf6a980> Operating System

Affected Configurations

Operator: OR

Vulnerable CPE
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:*

References

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