CVE-2026-23095gue: Fix skb memleak with inner IP protocol 0.
Updated under an hour ago ()
Does this affect you?
It affects Linux and 4 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
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
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 37dd0247797b168ad1cc7f5dbec825a1ee66535b before 886f186328b718400dbf79e1bc8cbcbd710ab766; from 37dd0247797b168ad1cc7f5dbec825a1ee66535b before 380a82d36e37db49fd41ecc378c22fd29392e96a; from 37dd0247797b168ad1cc7f5dbec825a1ee66535b before 536f5bbc322eb1e175bdd1ced22b236a951c4d8f; from 37dd0247797b168ad1cc7f5dbec825a1ee66535b before f87b9b7a618c82e7465e872eb10e14c803871892; from 37dd0247797b168ad1cc7f5dbec825a1ee66535b before ce569b389a5c78d64788a5ea94560e17fa574b35; from 37dd0247797b168ad1cc7f5dbec825a1ee66535b before 5437a279804ced8088cabb945dba88a26d828f8c; 37dd0247797b168ad1cc7f5dbec825a1ee66535b builds before 9a56796ad258786d3624eef5aefba394fc9bdded | CNA record |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.6 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 3.18 before 5.10.249; from 5.11 before 5.15.199; from 5.16 before 6.1.162; from 6.2 before 6.6.122; from 6.7 before 6.12.68; from 6.13 before 6.18.8; 6.19; 6.19; and 4 more ranges | NVD |
References
- https://git.kernel.org/stable/c/886f186328b718400dbf79e1bc8cbcbd710ab766patch
- https://git.kernel.org/stable/c/380a82d36e37db49fd41ecc378c22fd29392e96apatch
- https://git.kernel.org/stable/c/536f5bbc322eb1e175bdd1ced22b236a951c4d8fpatch
- https://git.kernel.org/stable/c/f87b9b7a618c82e7465e872eb10e14c803871892patch
- https://git.kernel.org/stable/c/ce569b389a5c78d64788a5ea94560e17fa574b35patch
- https://git.kernel.org/stable/c/5437a279804ced8088cabb945dba88a26d828f8cpatch
- https://git.kernel.org/stable/c/9a56796ad258786d3624eef5aefba394fc9bddedpatch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.