CVE-2023-53333

What it is

In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: dccp: copy entire header to stack buffer, not just basic one Eric Dumazet says: nf_conntrack_dccp_packet() has an unique: dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh); And nothing more is 'pulled' from the packet, depending on the content. dh->dccph_doff, and/or dh->dccph_x ...) So dccp_ack_seq() is happily reading stuff past the _dh buffer. BUG: KASAN: stack-out-of-bounds in nf_conntrack_dccp_packet+0x1134/0x11c0 Read of size 4 at addr ffff000128f66e0c by task syz-executor.2/29371 [..] Fix this by increasing the stack buffer to also include room for the extra sequence numbers and all the known dccp packet type headers, then pull again after the initial validation of the basic header. While at it, mark packets invalid that lack 48bit sequence bit but where RFC says the type MUST use them. Compile tested only. v2: first skb_header_pointer() now needs to adjust the size to only pull the generic header. (Eric) Heads-up: I intend to remove dccp conntrack support later this year.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-09-16 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-04 10:19 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 8.2 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-09-16 17:15 UTC

Last modified

2026-08-04 10:19 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-125 · Out-of-bounds read

Record status

Modified

Affected

• Linux Kernel < 5.4.251
• Linux Kernel < 5.10.188
• Linux Kernel < 5.15.121
• Linux Kernel < 6.1.39
• Linux Kernel < 6.3.13
• Linux Kernel < 6.4.4

Attack profile CVSS 3.1 · 8.2

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-53333.md and follow it. Check whether this project is affected by CVE-2023-53333. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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