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CVE PROGRAM SOURCE RECORD7.5 High

CVE-2026-23095

gue: Fix skb memleak with inner IP protocol 0.

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Status
Published
Published
Updated
Assigning organization
Linux

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

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 37dd0247797b168ad1cc7f5dbec825a1ee66535b to < 886f186328b718400dbf79e1bc8cbcbd710ab766affected
  • 37dd0247797b168ad1cc7f5dbec825a1ee66535b to < 380a82d36e37db49fd41ecc378c22fd29392e96aaffected
  • 37dd0247797b168ad1cc7f5dbec825a1ee66535b to < 536f5bbc322eb1e175bdd1ced22b236a951c4d8faffected
  • 37dd0247797b168ad1cc7f5dbec825a1ee66535b to < f87b9b7a618c82e7465e872eb10e14c803871892affected
  • 37dd0247797b168ad1cc7f5dbec825a1ee66535b to < ce569b389a5c78d64788a5ea94560e17fa574b35affected
  • 37dd0247797b168ad1cc7f5dbec825a1ee66535b to < 5437a279804ced8088cabb945dba88a26d828f8caffected
  • 37dd0247797b168ad1cc7f5dbec825a1ee66535b to < 9a56796ad258786d3624eef5aefba394fc9bddedaffected

Linux Linux

Default version status: affected

  • 3.18affected
  • 0 to < 3.18unaffected
  • 5.10.249 to ≤ 5.10.*unaffected
  • 5.15.199 to ≤ 5.15.*unaffected
  • 6.1.162 to ≤ 6.1.*unaffected
  • 6.6.122 to ≤ 6.6.*unaffected
  • 6.12.68 to ≤ 6.12.*unaffected
  • 6.18.8 to ≤ 6.18.*unaffected
  • 6.19 to ≤ *unaffected

References