CVE-2026-92238 Ambiguous parsing of mail headers
A malicious mail header can cause memory safety violations in Thunderbird, potentially allowing code execution or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-92238?
CVE-2026-92238 is a critical memory corruption vulnerability in Mozilla Thunderbird, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-444
Which versions are affected by CVE-2026-92238?
It affects 1 product.
Products include Mozilla Thunderbird.
How do I fix CVE-2026-92238?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-92238 being exploited?
There is no known exploitation of CVE-2026-92238 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Thunderbird
Sources
Also known as DEBIAN-CVE-2026-92238, GHSA-w2rw-r9p8-wp72, UBUNTU-CVE-2026-92238.