Mozilla Thunderbird up to 102.9 Garbage Collector memory corruption

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.
6.0	$5k-$25k	0.00

Summaryinfo

A vulnerability was found in Mozilla Thunderbird up to 102.9. It has been rated as critical. This vulnerability affects unknown code of the component Garbage Collector. This manipulation causes memory corruption. The identification of this vulnerability is CVE-2023-29535. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in Mozilla Thunderbird up to 102.9 (Mail Client Software). Affected by this vulnerability is an unknown function of the component Garbage Collector. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was shared 04/11/2023 by Lukas Bernhard as Bug 1820543 as confirmed advisory (Website). The advisory is shared at bugzilla.mozilla.org. The advisory contains:

Following a Garbage Collector compaction, weak maps may have been accessed before they were correctly traced. This resulted in memory corruption and a potentially exploitable crash.

This vulnerability is known as CVE-2023-29535. 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 $5k-$25k at the moment (estimation calculated on 12/10/2025).

The vulnerability scanner Nessus provides a plugin with the ID 239763 (TencentOS Server 4: thunderbird (TSSA-2024:0450)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 102.10 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (239763) and EUVD (EUVD-2023-33077). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Mail Client Software

Vendor

• Mozilla

Name

• Thunderbird

Version

• 102.0
• 102.1
• 102.2
• 102.3
• 102.4
• 102.5
• 102.6
• 102.7
• 102.8
• 102.9

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: 6.3
VulDB Meta Temp Score: 6.0

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

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: Memory corruption
CWE: CWE-119
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

Nessus ID: 239763
Nessus Name: TencentOS Server 4: thunderbird (TSSA-2024:0450)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Upgrade: Thunderbird 102.10

Timelineinfo

04/07/2023 🔍
04/11/2023 +4 days 🔍
04/11/2023 +0 days 🔍
04/14/2023 +3 days 🔍
12/10/2025 +971 days 🔍

Sourcesinfo

Vendor: mozilla.org

Advisory: Bug 1820543
Researcher: Lukas Bernhard
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2023-29535 (🔍)
GCVE (CVE): GCVE-0-2023-29535
GCVE (VulDB): GCVE-100-226009
EUVD: 🔍

Entryinfo

Created: 04/14/2023 16:43
Updated: 12/10/2025 12:06
Changes: 04/14/2023 16:43 (18), 04/14/2023 16:46 (28), 05/03/2023 13:42 (1), 06/20/2025 19:53 (17), 12/10/2025 12:06 (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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