CVE-2026-4371
Fixed in a distro release EPSS <1%CVSS 7.4
A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.
Products: Mozilla Thunderbird, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8.2 Advanced Update Support, Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On, Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.6 Telecommunications Update Service, Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions, Red Hat Enterprise Linux 8.8 Telecommunications Update Service, Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions, Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions, Red Hat Enterprise Linux 9.4 Extended Update Support, Red Hat Enterprise Linux 9.6 Extended Update Support, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| AlmaLinux 10 | thunderbird | 140.9.0-1.el10_1.alma.1 |
| AlmaLinux 8 | thunderbird | 140.9.0-1.el8_10.alma.1 |
| AlmaLinux 9 | thunderbird | 140.9.0-1.el9_7.alma.1 |
| Amazon Linux 2 | thunderbird | 140.9.0-1.amzn2.0.2 |
| Debian 11 | thunderbird | 1:140.9.0esr-1~deb11u1 |
| Debian 12 | thunderbird | 1:140.9.0esr-1~deb12u1 |
| Debian 13 | thunderbird | 1:140.9.0esr-1~deb13u1 |
| Debian 14 | thunderbird | 1:140.9.0esr-1 |
| Red Hat Enterprise Linux 10.1 | thunderbird | 0:140.9.0-1.el10_1 |
| Red Hat Enterprise Linux 10.1 | thunderbird-debuginfo | 0:140.9.0-1.el10_1 |
| Red Hat Enterprise Linux 10.1 | thunderbird-debugsource | 0:140.9.0-1.el10_1 |
| Red Hat Enterprise Linux 8 | thunderbird | 0:140.9.0-1.el8_10 |
| Red Hat Enterprise Linux 8 | thunderbird-debuginfo | 0:140.9.0-1.el8_10 |
| Red Hat Enterprise Linux 8 | thunderbird-debugsource | 0:140.9.0-1.el8_10 |
| Red Hat Enterprise Linux 9 | thunderbird | 0:140.9.0-1.el9_7 |
| Red Hat Enterprise Linux 9 | thunderbird-debuginfo | 0:140.9.0-1.el9_7 |
| Red Hat Enterprise Linux 9 | thunderbird-debugsource | 0:140.9.0-1.el9_7 |
| Red Hat Enterprise Linux eus 10.0 | thunderbird | 0:140.9.0-1.el10_0 |
| Red Hat Enterprise Linux eus 10.0 | thunderbird-debuginfo | 0:140.9.0-1.el10_0 |
| Red Hat Enterprise Linux eus 10.0 | thunderbird-debugsource | 0:140.9.0-1.el10_0 |
| Red Hat rhel aus 8.2 | thunderbird | 0:140.9.0-1.el8_2 |
| Red Hat rhel aus 8.2 | thunderbird-debuginfo | 0:140.9.0-1.el8_2 |
| Red Hat rhel aus 8.2 | thunderbird-debugsource | 0:140.9.0-1.el8_2 |
| Red Hat rhel aus 8.4 | thunderbird | 0:140.9.0-1.el8_4 |
| Red Hat rhel aus 8.4 | thunderbird-debuginfo | 0:140.9.0-1.el8_4 |
| Red Hat rhel aus 8.4 | thunderbird-debugsource | 0:140.9.0-1.el8_4 |
| Red Hat rhel aus 8.6 | thunderbird | 0:140.9.0-1.el8_6 |
| Red Hat rhel aus 8.6 | thunderbird-debuginfo | 0:140.9.0-1.el8_6 |
| Red Hat rhel aus 8.6 | thunderbird-debugsource | 0:140.9.0-1.el8_6 |
| Red Hat rhel e4s 8.6 | thunderbird | 0:140.9.0-1.el8_6 |
| Red Hat rhel e4s 8.6 | thunderbird-debuginfo | 0:140.9.0-1.el8_6 |
| Red Hat rhel e4s 8.6 | thunderbird-debugsource | 0:140.9.0-1.el8_6 |
| Red Hat rhel e4s 8.8 | thunderbird | 0:140.9.0-1.el8_8 |
| Red Hat rhel e4s 8.8 | thunderbird-debuginfo | 0:140.9.0-1.el8_8 |
| Red Hat rhel e4s 8.8 | thunderbird-debugsource | 0:140.9.0-1.el8_8 |
| Red Hat rhel e4s 9.0 | thunderbird | 0:140.9.0-1.el9_0 |
| Red Hat rhel e4s 9.0 | thunderbird-debuginfo | 0:140.9.0-1.el9_0 |
| Red Hat rhel e4s 9.0 | thunderbird-debugsource | 0:140.9.0-1.el9_0 |
| Red Hat rhel e4s 9.2 | thunderbird | 0:140.9.0-1.el9_2 |
| Red Hat rhel e4s 9.2 | thunderbird-debuginfo | 0:140.9.0-1.el9_2 |
| Red Hat rhel e4s 9.2 | thunderbird-debugsource | 0:140.9.0-1.el9_2 |
| Red Hat rhel eus 9.4 | thunderbird | 0:140.9.0-1.el9_4 |
| Red Hat rhel eus 9.4 | thunderbird-debuginfo | 0:140.9.0-1.el9_4 |
| Red Hat rhel eus 9.4 | thunderbird-debugsource | 0:140.9.0-1.el9_4 |
| Red Hat rhel eus 9.6 | thunderbird | 0:140.9.0-1.el9_6 |
| Red Hat rhel eus 9.6 | thunderbird-debuginfo | 0:140.9.0-1.el9_6 |
| Red Hat rhel eus 9.6 | thunderbird-debugsource | 0:140.9.0-1.el9_6 |
| Red Hat rhel eus long life 8.4 | thunderbird | 0:140.9.0-1.el8_4 |
| Red Hat rhel eus long life 8.4 | thunderbird-debuginfo | 0:140.9.0-1.el8_4 |
| Red Hat rhel eus long life 8.4 | thunderbird-debugsource | 0:140.9.0-1.el8_4 |
| Red Hat rhel tus 8.6 | thunderbird | 0:140.9.0-1.el8_6 |
| Red Hat rhel tus 8.6 | thunderbird-debuginfo | 0:140.9.0-1.el8_6 |
| Red Hat rhel tus 8.6 | thunderbird-debugsource | 0:140.9.0-1.el8_6 |
| Red Hat rhel tus 8.8 | thunderbird | 0:140.9.0-1.el8_8 |
| Red Hat rhel tus 8.8 | thunderbird-debuginfo | 0:140.9.0-1.el8_8 |
| Red Hat rhel tus 8.8 | thunderbird-debugsource | 0:140.9.0-1.el8_8 |
| Rocky Linux 10 | thunderbird | 0:140.9.0-1.el10_1 |
| Rocky Linux 8 | thunderbird | 0:140.9.0-1.el8_10 |
| Rocky Linux 9 | thunderbird | 0:140.9.0-1.el9_7 |
| Ubuntu 18.04 LTS | mozjs38 | no fix |
| Ubuntu 18.04 LTS | mozjs52 | no fix |
| Ubuntu 20.04 LTS | mozjs52 | no fix |
| Ubuntu 20.04 LTS | mozjs68 | no fix |
| Ubuntu 22.04 LTS | mozjs102 | no fix |
| Ubuntu 22.04 LTS | mozjs78 | no fix |
| Ubuntu 22.04 LTS | mozjs91 | no fix |
| Ubuntu 22.04 LTS | thunderbird | no fix |
| Ubuntu 24.04 LTS | mozjs102 | no fix |
| Ubuntu 24.04 LTS | mozjs115 | no fix |
| openSUSE Leap 15.6 | MozillaThunderbird | 140.9.0-150200.8.263.1 |
| openSUSE Tumbleweed | MozillaThunderbird | 140.9.0-1.1 |