Mozilla: >> Thunderbird Security Vulnerabilities
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.
CVSS Score
9.8
EPSS Score
0.005
Published
2026-09-15
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.
CVSS Score
8.1
EPSS Score
0.004
Published
2026-09-15
A 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. The affected parsing path is reachable before authentication. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
CVSS Score
9.1
EPSS Score
0.006
Published
2026-09-15
Mitigation bypass in the Networking component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
CVSS Score
9.1
EPSS Score
0.003
Published
2026-09-15
Incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-09-15
Denial-of-service in the SVG component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
CVSS Score
6.5
EPSS Score
0.003
Published
2026-09-15
Denial-of-service in the Security component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
CVSS Score
6.5
EPSS Score
0.002
Published
2026-09-15
Mitigation bypass in the Widget: Win32 component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
CVSS Score
9.1
EPSS Score
0.003
Published
2026-09-15
Incorrect boundary conditions in the Safe Browsing component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
CVSS Score
8.0
EPSS Score
0.002
Published
2026-09-15
Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
CVSS Score
8.8
EPSS Score
0.002
Published
2026-09-15