CVE-2026-92238Critical· 9.8▾ MidnightA maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 53.9 · 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 → 9.8
medium → critical
Last analysed / modified upstream
0.2% → 0.6%
A maliciously constructed mail header could lead to multiple fields being parsed as one, or potential memory safety violations. 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-2026-92239High· 8.1A maliciously constructed IMAP line could cause an out-of-bounds buffer read
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-2026-100793Medium· 6.5JIT miscompilation in the JavaScript Engine component
CVE-2026-100792High· 7.1JIT miscompilation in the JavaScript: WebAssembly component
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