Your submission was sent successfully! Close

You have successfully unsubscribed! Close

Thank you for signing up for our newsletter!
In these regular emails you will find the latest updates about Ubuntu and upcoming events where you can meet our team.Close

USN-4353-1: Firefox vulnerabilities

7 May 2020

Firefox could be made to crash or run programs as your login if it opened a malicious website.

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro



  • firefox - Mozilla Open Source web browser


Multiple security issues were discovered in Firefox. If a user were
tricked in to opening a specially crafted website, an attacker could
potentially exploit these to cause a denial of service, bypass security
restrictions, spoof the URL bar, or execute arbitrary code.
(CVE-2020-6831, CVE-2020-12387, CVE-2020-12390, CVE-2020-12391,
CVE-2020-12394, CVE-2020-12395, CVE-2020-12396)

It was discovered that the Devtools’ ‘Copy as cURL’ feature did not
properly escape the HTTP POST data of a request. If a user were tricked in to
using the ‘Copy as cURL’ feature to copy and paste a command with
specially crafted data in to a terminal, an attacker could potentially
exploit this to obtain sensitive information from local files.

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 20.04
Ubuntu 19.10
Ubuntu 18.04
Ubuntu 16.04

After a standard system update you need to restart Firefox to make
all the necessary changes.

Related notices

  • USN-4373-1: thunderbird-locale-ms, thunderbird-locale-cy, thunderbird-locale-fy, thunderbird-locale-kab, thunderbird-locale-zh-tw, xul-ext-gdata-provider, thunderbird-locale-cak, thunderbird-locale-en-gb, thunderbird-locale-ta, thunderbird-locale-ja, thunderbird-locale-pa-in, thunderbird-locale-pt, thunderbird-locale-ro, thunderbird-locale-ga, thunderbird-locale-ru, thunderbird-locale-zh-hans, thunderbird-locale-ast, thunderbird-locale-he, thunderbird-locale-kk, thunderbird-locale-da, thunderbird-locale-id, thunderbird-locale-af, thunderbird-locale-fr, thunderbird-locale-gl, thunderbird-locale-pt-pt, thunderbird-locale-el, thunderbird-locale-ca, thunderbird-gnome-support, thunderbird-locale-uk, thunderbird-mozsymbols, thunderbird-locale-lt, thunderbird-locale-hr, thunderbird-locale-eu, thunderbird-locale-zh-cn, thunderbird-locale-zh-hant, thunderbird-locale-sl, thunderbird-locale-gd, thunderbird-locale-tr, thunderbird-locale-vi, xul-ext-calendar-timezones, thunderbird-locale-es-es, thunderbird-dev, xul-ext-lightning, thunderbird-locale-bn-bd, thunderbird-locale-nb-no, thunderbird-locale-sq, thunderbird-locale-sk, thunderbird-locale-sr, thunderbird-locale-bg, thunderbird-locale-be, thunderbird-locale-es-ar, thunderbird-locale-nl, thunderbird-locale-nn-no, thunderbird-locale-it, thunderbird-locale-hu, thunderbird-locale-nb, thunderbird-locale-bn, thunderbird-locale-et, thunderbird-locale-ta-lk, thunderbird, thunderbird-locale-fi, thunderbird-locale-cs, thunderbird-locale-fy-nl, thunderbird-locale-ko, thunderbird-locale-si, thunderbird-locale-dsb, thunderbird-locale-en-us, thunderbird-locale-pl, thunderbird-locale-ga-ie, thunderbird-locale-sv-se, thunderbird-locale-mk, thunderbird-locale-nn, thunderbird-locale-is, thunderbird-locale-ka, thunderbird-locale-hsb, thunderbird-locale-pt-br, thunderbird-locale-pa, thunderbird-locale-en, thunderbird-locale-br, thunderbird-locale-ar, thunderbird-locale-de, thunderbird-locale-sv, thunderbird-locale-hy, thunderbird-locale-uz, thunderbird-locale-rm, thunderbird-locale-es