CVE-2026-92239High· 8.1▾ TwilightA maliciously constructed IMAP line could cause an out-of-bounds buffer read. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 44.6 · likelihood 0.1 · exploitation 0
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Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Sep 19.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
— → 6.1
none → medium
0.2%
6.1 → 8.1
medium → high
Last analysed / modified upstream
0.2% → 0.5%
A maliciously constructed IMAP line could cause an out-of-bounds buffer read. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
thunderbird < 140.16.0thunderbird >= 141.0, < 153.3.0thunderbird >= 154.0, < 156.0Upgrade past the affected range:
thunderbird 156.0Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-92240Critical· 9.1A 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
CVE-2026-92238Critical· 9.8A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations
CVE-2026-103500Medium· 6.1An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size
CVE-2026-100794Critical· 9.6Sandbox escape due to incorrect boundary conditions in the Internationalization component
CVE-2026-100788Critical· 9.8Invalid pointer in the JavaScript: WebAssembly component
CVE-2026-100793Medium· 6.5JIT miscompilation in the JavaScript Engine component