Linux Kernel up to 6.5.2 lwt use after free

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.6	$0-$5k	0.00

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.5.2. This impacts an unknown function of the component lwt. Performing a manipulation results in use after free. This vulnerability is cataloged as CVE-2023-53338. The attack must be initiated from a local position. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.5.2. This affects some unknown processing of the component lwt. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: lwt: Fix return values of BPF xmit ops BPF encap ops can return different types of positive values, such like NET_RX_DROP, NET_XMIT_CN, NETDEV_TX_BUSY, and so on, from function skb_do_redirect and bpf_lwt_xmit_reroute. At the xmit hook, such return values would be treated implicitly as LWTUNNEL_XMIT_CONTINUE in ip(6)_finish_output2. When this happens, skbs that have been freed would continue to the neighbor subsystem, causing use-after-free bug and kernel crashes. To fix the incorrect behavior, skb_do_redirect return values can be simply discarded, the same as tc-egress behavior. On the other hand, bpf_lwt_xmit_reroute returns useful errors to local senders, e.g. PMTU information. Thus convert its return values to avoid the conflict with LWTUNNEL_XMIT_CONTINUE.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2023-53338 since 09/16/2025. The exploitability is told to be easy. An attack has to be approached locally. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/27/2025).

The vulnerability scanner Nessus provides a plugin with the ID 265614 (Linux Distros Unpatched Vulnerability : CVE-2023-53338), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.257, 5.10.195, 5.15.132, 6.1.53, 6.4.16 or 6.5.3 eliminates this vulnerability. Applying the patch 67f8f2bae8e7ac72e09def2b667e44704c4d1ee1/a97f221651fcdc891166e9bc270e3d9bfa5a0080/e3f647e4b642f9f6d32795a16f92c116c138d2af/065d5f17096ec9161180e2c890afdff4dc6125f2/d68c17402442f5f494a2c3ebde5cb82f6aa9160a/65583f9e070db7bece20710cfa2e3daeb0b831d9/29b22badb7a84b783e3a4fffca16f7768fb31205 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (265614) and CERT Bund (WID-SEC-2025-2087). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Amazon Linux 2
• Red Hat Enterprise Linux
• SUSE Linux
• Oracle Linux
• IBM QRadar SIEM
• Open Source Linux Kernel
• RESF Rocky Linux
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.4.256
• 5.10.194
• 5.15.131
• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.1.22
• 6.1.23
• 6.1.24
• 6.1.25
• 6.1.26
• 6.1.27
• 6.1.28
• 6.1.29
• 6.1.30
• 6.1.31
• 6.1.32
• 6.1.33
• 6.1.34
• 6.1.35
• 6.1.36
• 6.1.37
• 6.1.38
• 6.1.39
• 6.1.40
• 6.1.41
• 6.1.42
• 6.1.43
• 6.1.44
• 6.1.45
• 6.1.46
• 6.1.47
• 6.1.48
• 6.1.49
• 6.1.50
• 6.1.51
• 6.1.52
• 6.4.0
• 6.4.1
• 6.4.2
• 6.4.3
• 6.4.4
• 6.4.5
• 6.4.6
• 6.4.7
• 6.4.8
• 6.4.9
• 6.4.10
• 6.4.11
• 6.4.12
• 6.4.13
• 6.4.14
• 6.4.15
• 6.5.0
• 6.5.1
• 6.5.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
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CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.8
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.8
VulDB Temp Score: 7.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 265614
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2023-53338

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.4.257/5.10.195/5.15.132/6.1.53/6.4.16/6.5.3
Patch: 67f8f2bae8e7ac72e09def2b667e44704c4d1ee1/a97f221651fcdc891166e9bc270e3d9bfa5a0080/e3f647e4b642f9f6d32795a16f92c116c138d2af/065d5f17096ec9161180e2c890afdff4dc6125f2/d68c17402442f5f494a2c3ebde5cb82f6aa9160a/65583f9e070db7bece20710cfa2e3daeb0b831d9/29b22badb7a84b783e3a4fffca16f7768fb31205

Timelineinfo

09/16/2025 CVE reserved
09/17/2025 +1 days Advisory disclosed
09/17/2025 +0 days VulDB entry created
12/27/2025 +101 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2023-53338 (🔒)
GCVE (CVE): GCVE-0-2023-53338
GCVE (VulDB): GCVE-100-324729
CERT Bund: WID-SEC-2025-2087 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 09/17/2025 18:07
Updated: 12/27/2025 03:21
Changes: 09/17/2025 18:07 (58), 09/21/2025 21:17 (2), 12/11/2025 17:06 (10), 12/27/2025 03:21 (7)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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