# CVE-2026-98300: tcp: Don't call skb_clone_and_charge_r() for close()d listener in tcp_v6_do_rcv().

> A race condition in the Linux kernel TCP IPv6 receive path can cause a kernel warning and potential denial of service when a listener is closed concurrently.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106080, BELL-CVE-2026-98300, DEBIAN-CVE-2026-98300, GHSA-jr77-63hq-vhgr, UBUNTU-CVE-2026-98300

## What is CVE-2026-98300?

CVE-2026-98300 is a vulnerability in Linux, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

tcp: Don't call skb_clone_and_charge_r() for close()d listener in tcp_v6_do_rcv().

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>

## Which versions are affected by CVE-2026-98300?


## How do I fix CVE-2026-98300?

Apply the vendor's patch.

## Is CVE-2026-98300 being exploited?

There is no known exploitation of CVE-2026-98300 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98300 and fix it if it is affected.

What it is: CVE-2026-98300 is a vulnerability in Linux, published on 6 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98300 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-98300/ (Markdown: https://insights.sbomify.com/CVE-2026-98300/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98300
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98300
- OSV: https://osv.dev/vulnerability/CVE-2026-98300

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98300/
Summaries are generated and may contain mistakes; the official description above is the record.