CVE-2026-110249
High
Description
A malicious, compromised, or MITM-controlled Exchange server can return a single well-formed SOAP response containing an element with enough attributes to keep Thunderbird's main thread CPU-bound for seconds to hours. This vulnerability was fixed in Thunderbird 158 and Thunderbird 153.5.
SeverityHigh
CVSS8.6
Exploit probability—
ProductThunderbird
PublishedOct 13, 2026
First seenOct 13, 2026
Weakness typeCWE-400Uncontrolled resource consumption
How to fix
Update
- Thunderbird158, 153.5 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Thunderbird | No range specified | 158, 153.5 |
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