Mozilla Thunderbird up to 91.4 XSLT Markup access control

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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8.0$0-$5k0.00

Summaryinfo

A vulnerability described as critical has been identified in Mozilla Thunderbird up to 91.4. This affects an unknown function of the component XSLT Markup Handler. The manipulation results in access control. This vulnerability is cataloged as CVE-2021-4140. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical has been found in Mozilla Thunderbird up to 91.4 (Mail Client Software). Affected is an unknown code block of the component XSLT Markup Handler. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

It was possible to construct specific XSLT markup that would be able to bypass an iframe sandbox. This vulnerability affects Firefox ESR < 91.5, Firefox < 96, and Thunderbird < 91.5.

The weakness was shared 01/11/2022 by Peter Van der Beken as Bug 1746720 as confirmed advisory (Website). The advisory is shared for download at bugzilla.mozilla.org. The advisory contains:

It was possible to construct specific XSLT markup that would be able to bypass an iframe sandbox.
This vulnerability is traded as CVE-2021-4140. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/16/2025). The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 91.5 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

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Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.1
VulDB Meta Temp Score: 8.0

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

NVD Base Score: 10.0
NVD Vector: 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
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: Upgrade
Status: 🔍

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

Upgrade: Thunderbird 91.5

Timelineinfo

12/20/2021 🔍
01/11/2022 +22 days 🔍
01/11/2022 +0 days 🔍
09/29/2022 +261 days 🔍
04/16/2025 +930 days 🔍

Sourcesinfo

Vendor: mozilla.org

Advisory: Bug 1746720
Researcher: Peter Van der Beken
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2021-4140 (🔍)
GCVE (CVE): GCVE-0-2021-4140
GCVE (VulDB): GCVE-100-209844

Entryinfo

Created: 09/29/2022 15:40
Updated: 04/16/2025 18:35
Changes: 09/29/2022 15:40 (18), 09/29/2022 15:43 (28), 10/25/2022 17:10 (1), 04/16/2025 18:35 (27)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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