CVE-2026-98300

What the bug is

tcp_v6_do_rcv() no longer calls skb_clone_and_charge_r() for TCP_LISTEN since commit 073d89808c06 ("net: fix data-races around sk->sk_forward_alloc"). However, there is still a small race window between tcp_v6_rcv() and tcp_v6_do_rcv(), where concurrent close() changes TCP_LISTEN to TCP_CLOSE, causing skb_clone_and_charge_r() to be called locklessly and resulting in the splat below. [0] Let's avoid calling skb_clone_and_charge_r() for TCP_CLOSE as well. This is fine for non-listeners because tcp_rcv_state_process() drops skb for TCP_CLOSE and opt_skb was freed immediately anyway. [0]: sk->sk_forward_alloc WARNING: net/ipv4/af_inet.c:162 at inet_sock_destruct+0x64d/0x810 net/ipv4/af_inet.c:162, CPU#1: ksoftirqd/1/28 Modules linked in: CPU: 1 UID: 0 PID: 28 Comm: ksoftirqd/1 Not tainted 7.2.0 #17 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 RIP: 0010:inet_sock_destruct+0x64d/0x810 net/ipv4/af_inet.c:162 Code: 3d 49 ff e9 06 fd ff ff e8 d0 5b 83 f8 90 0f 0b 90 e9 35 fe ff ff e8 c2 5b 83 f8 90 0f 0b 90 e9 c5 fe ff ff e8 b4 5b 83 f8 90 <0f> 0b 90 e9 04 ff ff ff e8 a6 5b 83 f8 90 0f 0b 90 e9 65 fe ff ff RSP: 0018:ffffc90000677bb8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8880117bde80 RCX: ffffffff8957eb41 RDX: ffff88801dad5d00 RSI: ffffffff8957ec3c RDI: 0000000000000005 RBP: 00000000fffff000 R08: ffffffff8957eb41 R09: 00000000fffff000 R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff8880117bdf10 R14: ffffffff81c08eb7 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8880d7ae5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f93a1021138 CR3: 00000000207a9000 CR4: 0000000000350ef0 Call Trace: <TASK> __sk_destruct+0x82/0xae0 net/core/sock.c:2356 rcu_do_batch kernel/rcu/tree.c:2645 [inline] rcu_core+0x59c/0x1100 kernel/rcu/tree.c:2897 handle_softirqs+0x1e4/0x9b0 kernel/softirq.c:622 run_ksoftirqd kernel/softirq.c:1076 [inline] run_ksoftirqd+0x38/0x60 kernel/softirq.c:1068 smpboot_thread_fn+0x458/0xc80 kernel/smpboot.c:160 kthread+0x396/0x4a0 kernel/kthread.c:436 ret_from_fork+0x8e0/0xe40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK>

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

net/ipv6/tcp_ipv6.c

What this is

NETWORKING [TCP]MAINTAINERS section matched on net/ipv6/tcp*.c · netdev@vger.kernel.org · Maintained

Check it on the machine

grep -w CONFIG_IPV6 /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

Show whether Debian builds this, per release

Debian builds this code. Every release below compiles the affected file into the kernels it ships.

• bookworm, trixie, forky, sidy

y

built into the kernel image on every flavour - only a patch removes it

Build switch

CONFIG_IPV6

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-10-06 (13 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.18%, higher than 6.7% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

net/ipv6

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
4.4	5.10.271	a23a3bc5004d
4.4	5.15.222	1cb7f292a337
4.4	6.1.189	7d94602e77a4
4.4	6.6.158	b727e3d58cb9
4.4	6.12.112	3e3394a13b60
4.4	6.18.54	619bfbaacbff
4.4	7.2.8	56d38839ef0b
4.4	7.3	8e759cd1f644

Debian advisories