VDB-239057 · CVE-2023-4809 · GCVE-0-2023-4809

FreeBSD IPv6 Fragmented Packet additional special element

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.
6.3	$0-$5k	0.00

Summaryinfo

A vulnerability was found in FreeBSD. It has been rated as problematic. Impacted is an unknown function of the component IPv6 Fragmented Packet Handler. The manipulation leads to improper handling of additional special element. This vulnerability is uniquely identified as CVE-2023-4809. The attack is possible to be carried out remotely. No exploit exists. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability was found in FreeBSD (Operating System) (version unknown). It has been rated as problematic. This issue affects an unknown function of the component IPv6 Fragmented Packet Handler. The manipulation with an unknown input leads to a improper handling of additional special element vulnerability. Using CWE to declare the problem leads to CWE-167. The product receives input from an upstream component, but it does not handle or incorrectly handles when an additional unexpected special element is provided. Impacted is integrity. The summary by CVE is:

In pf packet processing with a 'scrub fragment reassemble' rule, a packet containing multiple IPv6 fragment headers would be reassembled, and then immediately processed. That is, a packet with multiple fragment extension headers would not be recognized as the correct ultimate payload. Instead a packet with multiple IPv6 fragment headers would unexpectedly be interpreted as a fragmented packet, rather than as whatever the real payload is. As a result, IPv6 fragments may bypass pf firewall rules written on the assumption all fragments have been reassembled and, as a result, be forwarded or processed by the host.

The weakness was disclosed 09/07/2023. The advisory is shared at security.FreeBSD.org. The identification of this vulnerability is CVE-2023-4809 since 09/06/2023. 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 02/14/2025).

Applying a patch is able to eliminate this problem.

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

Productinfo

Type

Operating System

Name

FreeBSD

License

open-source

Website

Product: https://www.freebsd.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper handling of additional special element
CWE: CWE-167 / CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Timelineinfo

09/06/2023 🔍
09/06/2023 +0 days 🔍
09/07/2023 +0 days 🔍
02/14/2025 +526 days 🔍

Sourcesinfo

Product: freebsd.org

Advisory: security.FreeBSD.org
Status: Confirmed

CVE: CVE-2023-4809 (🔍)
GCVE (CVE): GCVE-0-2023-4809
GCVE (VulDB): GCVE-100-239057

Entryinfo

Created: 09/07/2023 01:09
Updated: 02/14/2025 06:57
Changes: 09/07/2023 01:09 (37), 02/14/2025 06:57 (27)
Complete: 🔍
Cache ID: 216::103