Mozilla Firefox up to 108 ParseFromSafeString Remote Code Execution

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 Mozilla Firefox up to 108. It has been classified as critical. Impacted is the function DOMParser::ParseFromSafeString. The manipulation leads to an unknown weakness. This vulnerability is listed as CVE-2023-23604. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Mozilla Firefox up to 108 (Web Browser) and classified as critical. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A duplicate `SystemPrincipal` object could be created when parsing a non-system html document via `DOMParser::ParseFromSafeString`. This could have lead to bypassing web security checks. This vulnerability affects Firefox < 109.

The weakness was presented 01/17/2023 by Nika Layzell as Bug 1802346 as confirmed advisory (Website). The advisory is shared at bugzilla.mozilla.org. The advisory contains:

A duplicate SystemPrincipal object could be created when parsing a non-system html document via DOMParser::ParseFromSafeString. This could have lead to bypassing web security checks.

The identification of this vulnerability is CVE-2023-23604. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/18/2025).

Upgrading to version 109 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2023-27704). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Web Browser

Vendor

• Mozilla

Name

• Firefox

Version

• 108

License

• open-source

Website

• Vendor: https://www.mozilla.org/
• Product: https://www.mozilla.org/en-US/firefox/

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: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 6.5
NVD Vector: 🔍

CNA Base Score: 6.5
CNA 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: Remote Code Execution
CWE: Unknown
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Upgrade: Firefox 109

Timelineinfo

01/16/2023 🔍
01/17/2023 +1 days 🔍
01/17/2023 +0 days 🔍
01/19/2023 +2 days 🔍
12/18/2025 +1064 days 🔍

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: Bug 1802346
Researcher: Nika Layzell
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2023-23604 (🔍)
GCVE (CVE): GCVE-0-2023-23604
GCVE (VulDB): GCVE-100-218993
EUVD: 🔍

Entryinfo

Created: 01/19/2023 14:22
Updated: 12/18/2025 20:58
Changes: 01/19/2023 14:22 (17), 01/19/2023 14:25 (28), 02/15/2023 13:21 (1), 01/10/2025 21:49 (35), 04/28/2025 04:43 (3), 10/14/2025 05:27 (1), 12/18/2025 20:58 (1)
Complete: 🔍
Cache ID: 216::103

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

Discussion

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