CVE-2026-23095 [High] | Information Disclosure in Linux Kernel

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

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.02%	0.24%	+0.22%
2	2026-02-05	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.02%

0.24%

+0.22%

2026-02-05

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	416baaa9-dc9f-4396-8d5f-8c081fb06d67
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.5

3.1

HIGH

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

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

3.6

416baaa9-dc9f-4396-8d5f-8c081fb06d67

5.5

3.1

MEDIUM

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

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

OS Trackers for CVE-2026-23095

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2026-23095 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6.	https://security-tracker.debian.org/tracker/CVE-2026-23095
`redhat`	—	—	https://access.redhat.com/security/cve/CVE-2026-23095
`suse`	medium	CVE-2026-23095 severity moderate: SUSE including 418 source package names (2.1.3-6.124:kernel-default-base-6.4.0-40.1.21.17, 2.1.3-7.105:kernel-default-6.4.0-40.1, …), 608 product×package rows across 38 product lines (Container suse/sl-micro/6.0/base-os-container, Container suse/sl-micro/6.0/kvm-os-container, … (38 product lines)): Fixed 341, Known Affected 231, First Fixed 32, Known Not Affected 4.	https://www.suse.com/security/cve/CVE-2026-23095/
`ubuntu`	medium	CVE-2026-23095 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1256 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): DNE 871, ignored 172, released 102, needed 93, pending 16, not-affected 2.	https://ubuntu.com/security/CVE-2026-23095

Affected software / configurations for CVE-2026-23095

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 3.18, < 5.10.249	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.11, < 5.15.199	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 6.1.162	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.2, < 6.6.122	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.7, < 6.12.68	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.13, < 6.18.8	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.19	cpe:2.3:o:linux:linux_kernel:6.19:rc1::::::
linux	linux_kernel	6.19	cpe:2.3:o:linux:linux_kernel:6.19:rc2::::::
linux	linux_kernel	6.19	cpe:2.3:o:linux:linux_kernel:6.19:rc3::::::
linux	linux_kernel	6.19	cpe:2.3:o:linux:linux_kernel:6.19:rc4::::::
linux	linux_kernel	6.19	cpe:2.3:o:linux:linux_kernel:6.19:rc5::::::
linux	linux_kernel	6.19	cpe:2.3:o:linux:linux_kernel:6.19:rc6::::::

References for CVE-2026-23095

URL	Tags
https://git.kernel.org/stable/c/380a82d36e37db49fd41ecc378c22fd29392e96a	Patch
https://git.kernel.org/stable/c/536f5bbc322eb1e175bdd1ced22b236a951c4d8f	Patch
https://git.kernel.org/stable/c/5437a279804ced8088cabb945dba88a26d828f8c	Patch
https://git.kernel.org/stable/c/886f186328b718400dbf79e1bc8cbcbd710ab766	Patch
https://git.kernel.org/stable/c/9a56796ad258786d3624eef5aefba394fc9bdded	Patch
https://git.kernel.org/stable/c/ce569b389a5c78d64788a5ea94560e17fa574b35	Patch
https://git.kernel.org/stable/c/f87b9b7a618c82e7465e872eb10e14c803871892	Patch

URL

CVE-2026-23095 | gue: Fix skb memleak with inner IP protocol 0.

Exploit prediction scoring system (EPSS) score for CVE-2026-23095

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23095

Weakness enumeration for CVE-2026-23095

OS Trackers for CVE-2026-23095

Affected software / configurations for CVE-2026-23095

References for CVE-2026-23095