Mozilla Thunderbird up to 91.10/101 CSS cross-domain policy

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.
6.2	$5k-$25k	0.00

Summaryinfo

A vulnerability was found in Mozilla Thunderbird up to 91.10/101. It has been rated as critical. This vulnerability affects unknown code of the component CSS Handler. The manipulation leads to cross-domain policy. This vulnerability is listed as CVE-2022-31744. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Mozilla Thunderbird up to 91.10/101 (Mail Client Software) and classified as critical. This issue affects an unknown function of the component CSS Handler. The manipulation with an unknown input leads to a cross-domain policy vulnerability. Using CWE to declare the problem leads to CWE-942. The product uses a cross-domain policy file that includes domains that should not be trusted. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

An attacker could have injected CSS into stylesheets accessible via internal URIs, such as resource:, and in doing so bypass a page's Content Security Policy. This vulnerability affects Firefox ESR < 91.11, Thunderbird < 102, Thunderbird < 91.11, and Firefox < 101.

The weakness was presented 06/28/2022 by Gertjan as Bug 1757604 as confirmed advisory (Website). The advisory is shared at bugzilla.mozilla.org. The advisory contains:

An attacker could have injected CSS into stylesheets accessible via internal URIs, such as resource:, and in doing so bypass a page's Content Security Policy.

The identification of this vulnerability is CVE-2022-31744. 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 04/15/2025).

Upgrading to version 91.11 or 102 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

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

Productinfo

Type

• Mail Client Software

Vendor

• Mozilla

Name

• Thunderbird

Version

• 91.0
• 91.1
• 91.2
• 91.3
• 91.4
• 91.5
• 91.6
• 91.7
• 91.8
• 91.9
• 91.10
• 101

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: 6.4
VulDB Meta Temp Score: 6.2

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

NVD Base Score: 6.5
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: Cross-domain policy
CWE: CWE-942 / CWE-346 / CWE-345
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: Thunderbird 91.11/102

Timelineinfo

05/26/2022 🔍
06/28/2022 +33 days 🔍
06/28/2022 +0 days 🔍
09/30/2022 +94 days 🔍
04/15/2025 +928 days 🔍

Sourcesinfo

Vendor: mozilla.org

Advisory: Bug 1757604
Researcher: Gertjan
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2022-31744 (🔍)
GCVE (CVE): GCVE-0-2022-31744
GCVE (VulDB): GCVE-100-209993

Entryinfo

Created: 09/30/2022 10:56
Updated: 04/15/2025 21:34
Changes: 09/30/2022 10:56 (17), 09/30/2022 10:59 (29), 10/26/2022 18:04 (1), 04/15/2025 21:34 (27)
Complete: 🔍
Cache ID: 216::103

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

Discussion

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