Skip to main content
cve.nowby Sazabi
← All vulnerabilities
CVE-2026-23095

gue: Fix skb memleak with inner IP protocol 0.

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.249, 5.15.199, 6.1.162, 6.6.122, 6.12.68, and 1 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

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

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From 37dd0247797b168ad1cc7f5dbec825a1ee66535b · fixed in 886f186328b718400dbf79e1bc8cbcbd710ab766; From 37dd0247797b168ad1cc7f5dbec825a1ee66535b · fixed in 380a82d36e37db49fd41ecc378c22fd29392e96a; From 37dd0247797b168ad1cc7f5dbec825a1ee66535b · fixed in 536f5bbc322eb1e175bdd1ced22b236a951c4d8f; From 37dd0247797b168ad1cc7f5dbec825a1ee66535b · fixed in f87b9b7a618c82e7465e872eb10e14c803871892; From 37dd0247797b168ad1cc7f5dbec825a1ee66535b · fixed in ce569b389a5c78d64788a5ea94560e17fa574b35; From 37dd0247797b168ad1cc7f5dbec825a1ee66535b · fixed in 5437a279804ced8088cabb945dba88a26d828f8c; From 37dd0247797b168ad1cc7f5dbec825a1ee66535b · fixed in 9a56796ad258786d3624eef5aefba394fc9bdded

  • Linux Linux

    3.18

  • KernelLinux

    From 3.18.0 · fixed in 5.10.249; From 5.11.0 · fixed in 5.15.199; From 5.16.0 · fixed in 6.1.162; From 6.2.0 · fixed in 6.6.122; From 6.7.0 · fixed in 6.12.68; From 6.13.0 · fixed in 6.18.8

References 7

git.kernel.org