7.5
High
CVE-2026-84641 A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response
Description
A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
Affected products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| Thunderbird 155 | earliest → < 155 | 155 |
| Thunderbird 153.2 | earliest → < 153.2 | 153.2 |
| Thunderbird 140.15 | earliest → < 140.15 | 140.15 |
Other CVEs of Thunderbird
The 1713 CVEs of Thunderbird →
CVE-2026-118180
Matrix homeserver could redirect the chat session to a local file or network share
7.5
High
CVE-2026-118179
Request forgery via news: links
8.8
High
CVE-2026-118177
Calendar discovery accepted local file and remote network share locations
9.1
Critical
CVE-2026-118178
RSS feed could redirect its subscription to a local file or network share
5.7
Medium