CVE-2020-26970 Memory corruption in Thunderbird

Q: Is CVE-2020-26970 being exploited?

There is no known exploitation of CVE-2020-26970 in the wild and no public exploit code.

High 8.8 Published 9 Dec 2020 Updated 4 Aug 2024

Stack corruption in Thunderbird's SMTP status code handling allows potential arbitrary code execution via crafted server responses.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2020-26970?

CVE-2020-26970 is a high-severity memory corruption vulnerability in Mozilla Thunderbird, published on 9 Dec 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

When reading SMTP server status codes, Thunderbird writes an integer value to a position on the stack that is intended to contain just one byte. Depending on processor architecture and stack layout, this leads to stack corruption that may be exploitable. This vulnerability affects Thunderbird < 78.5.1.

Weakness: CWE-787

Which versions are affected by CVE-2020-26970?

It affects 1 product.

Linux distribution packages (13)

`thunderbird` Red Hat:enterprise_linux:7::client	All versions	`0:78.5.1-1.el7_9`
`thunderbird-debuginfo` Red Hat:enterprise_linux:7::client	All versions	`0:78.5.1-1.el7_9`
`thunderbird` Red Hat:enterprise_linux:7::server	All versions	`0:78.5.1-1.el7_9`
`thunderbird-debuginfo` Red Hat:enterprise_linux:7::server	All versions	`0:78.5.1-1.el7_9`
`thunderbird` Red Hat:enterprise_linux:7::workstation	All versions	`0:78.5.1-1.el7_9`
`thunderbird-debuginfo` Red Hat:enterprise_linux:7::workstation	All versions	`0:78.5.1-1.el7_9`
`thunderbird` Red Hat:enterprise_linux:8::appstream	All versions	`0:78.5.1-1.el8_3`
`thunderbird-debuginfo` Red Hat:enterprise_linux:8::appstream	All versions	`0:78.5.1-1.el8_3`
`thunderbird-debugsource` Red Hat:enterprise_linux:8::appstream	All versions	`0:78.5.1-1.el8_3`
`thunderbird` Red Hat:rhel_eus:8.2::appstream	All versions	`0:78.5.1-1.el8_2`
`thunderbird-debuginfo` Red Hat:rhel_eus:8.2::appstream	All versions	`0:78.5.1-1.el8_2`
`thunderbird-debugsource` Red Hat:rhel_eus:8.2::appstream	All versions	`0:78.5.1-1.el8_2`
`MozillaThunderbird` SUSE:Linux Enterprise Workstation Extension 15 SP1	All versions	`78.5.1-3.110.2`

Products include Mozilla Thunderbird.

How do I fix CVE-2020-26970?

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-2020-26970 being exploited?

There is no known exploitation of CVE-2020-26970 in the wild and no public exploit code.

All Mozilla Thunderbird vulnerabilities

Sources

Also known as DEBIAN-CVE-2020-26970, DLA-2479-1, DSA-4802-1, GHSA-w8wp-h42w-f3m4, MGASA-2020-0450, RHSA-2020:5398 and 4 more.