Mozilla Thunderbird up to 140.15/155 IMAP Response Parser out-of-bounds

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.0$0-$5k0.45

Summaryinfo

A vulnerability classified as critical has been found in Mozilla Thunderbird up to 140.15/155. Affected by this issue is some unknown functionality of the component IMAP Response Parser. The manipulation leads to out-of-bounds. This vulnerability is traded as CVE-2026-92240. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Mozilla Thunderbird up to 140.15/155. This issue affects some unknown processing of the component IMAP Response Parser. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged '* ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. This vulnerability was fixed in Thunderbird 156 and Thunderbird 140.16.

The advisory is shared at bugzilla.mozilla.org. The identification of this vulnerability is CVE-2026-92240 since 09/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. 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 09/15/2026).

Upgrading to version 140.16 or 156 eliminates this vulnerability.

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Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Thunderbird 140.16/156

Timelineinfo

09/15/2026 Advisory disclosed
09/15/2026 +0 days CVE reserved
09/15/2026 +0 days VulDB entry created
09/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-92240 (🔒)
GCVE (CVE): GCVE-0-2026-92240
GCVE (VulDB): GCVE-100-404669

Entryinfo

Created: 09/15/2026 22:09
Changes: 09/15/2026 22:09 (57)
Complete: 🔍
Cache ID: 216::103

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