VDB-230609 · CVE-2023-23603 · EUVD-2023-27703

Mozilla Thunderbird up to 102.6 URL incorrect regex

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.
5.7	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Mozilla Thunderbird up to 102.6. Impacted is an unknown function of the component URL Handler. The manipulation leads to incorrect regex. This vulnerability is traded as CVE-2023-23603. It is possible to initiate the attack remotely. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Mozilla Thunderbird up to 102.6 (Mail Client Software). This issue affects an unknown functionality of the component URL Handler. The manipulation with an unknown input leads to a incorrect regex vulnerability. Using CWE to declare the problem leads to CWE-185. The product specifies a regular expression in a way that causes data to be improperly matched or compared. Impacted is confidentiality. The summary by CVE is:

Regular expressions used to filter out forbidden properties and values from style directives in calls to `console.log` weren't accounting for external URLs. Data could then be potentially exfiltrated from the browser. This vulnerability affects Firefox < 109, Firefox ESR < 102.7, and Thunderbird < 102.7.

The weakness was shared 06/03/2023. The advisory is shared at mozilla.org. The identification of this vulnerability is CVE-2023-23603 since 01/16/2023. It demands that the victim is doing some kind of user interaction. 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 12/18/2025).

Upgrading to version 102.7 eliminates this vulnerability. The upgrade is hosted for download at mozilla.org.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2023-27703). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Mail Client Software

Vendor

Mozilla

Name

Thunderbird

Version

License

open-source

Website

Vendor: https://www.mozilla.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.8
VulDB Meta Temp Score: 5.7

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
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: Incorrect regex
CWE: CWE-185 / CWE-697
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: 🔍

0-Day Time: 🔍

Upgrade: Thunderbird 102.7

Timelineinfo

01/16/2023 🔍
06/03/2023 +137 days 🔍
06/03/2023 +0 days 🔍
12/18/2025 +929 days 🔍

Sourcesinfo

Vendor: mozilla.org

Advisory: mozilla.org
Status: Confirmed

CVE: CVE-2023-23603 (🔍)
GCVE (CVE): GCVE-0-2023-23603
GCVE (VulDB): GCVE-100-230609
EUVD: 🔍

Entryinfo

Created: 06/03/2023 07:37
Updated: 12/18/2025 20:58
Changes: 06/03/2023 07:37 (41), 06/29/2023 17:33 (11), 01/10/2025 21:49 (26), 04/26/2025 00:41 (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.