[GH-ISSUE #6883] firefox: ~/.mailcap should be whitelisted to get the default helper applications #3408

New issue

Closed

opened 2026-05-05 09:58:14 -06:00 by gitea-mirror · 0 comments

gitea-mirror commented

2026-05-05 09:58:14 -06:00

Owner

Originally created by @vinc17fr on GitHub (Aug 30, 2025).
Original GitHub issue: https://github.com/netblue30/firejail/issues/6883

Description

When Firefox is run in firejail, Firefox fails to get the helper applications set up by the user; see Mozilla bug 1985743.

Steps to Reproduce

Run Firefox in firejail with the firefox profile.
In the Firefox settings, for "Applications", set "Portable Document Format (PDF)" to "Always ask".
Click on a link providing a PDF file.

Expected behavior

Firefox should propose the application configured by the user.

Actual behavior

Firefox proposes an arbitrary application (Inkscape in my case, which is a very poor choice).

Additional context

As I've found in Mozilla bug 1985743 comment 4 from the logs, Firefox uses the ~/.mailcap file. But this file is not whitelisted by the firefox profile. Adding

whitelist ${HOME}/.mailcap

in firefox-common.local solves this problem. So this is what should be done in the official profile.

Environment

Name/version/arch of the Linux kernel (uname -srm): Linux 6.16.3+deb14-amd64 x86_64
Name/version of the Linux distribution (e.g. "Ubuntu 20.04" or "Arch Linux"): Debian/unstable
Name/version of the relevant program(s)/package(s) (e.g. "firefox 134.0-1,
mesa 1:24.3.3-2"): Firefox since at least version 119 (and Nightly affected too)
Version of Firejail (firejail --version): 0.9.76

Checklist

The issues is caused by firejail (i.e. running the program by path (e.g. /usr/bin/vlc) "fixes" it).
I can reproduce the issue without custom modifications (e.g. globals.local).
The program has a profile. (If not, request one in https://github.com/netblue30/firejail/issues/1139)
The profile (and redirect profile if exists) hasn't already been fixed upstream.
I have performed a short search for similar issues (to avoid opening a duplicate).
- I'm aware of browser-allow-drm yes/browser-disable-u2f no in firejail.config to allow DRM/U2F in browsers.
I used --profile=PROFILENAME to set the right profile. (Only relevant for AppImages)

Originally created by @vinc17fr on GitHub (Aug 30, 2025). Original GitHub issue: https://github.com/netblue30/firejail/issues/6883 ### Description When Firefox is run in firejail, Firefox fails to get the helper applications set up by the user; see [Mozilla bug 1985743](https://bugzilla.mozilla.org/show_bug.cgi?id=1985743). ### Steps to Reproduce 1. Run Firefox in firejail with the `firefox` profile. 2. In the Firefox settings, for "Applications", set "Portable Document Format (PDF)" to "Always ask". 3. Click on a link providing a PDF file. ### Expected behavior Firefox should propose the application configured by the user. ### Actual behavior Firefox proposes an arbitrary application (Inkscape in my case, which is a very poor choice). ### Additional context As I've found in [Mozilla bug 1985743 comment 4](https://bugzilla.mozilla.org/show_bug.cgi?id=1985743#c4) from the logs, Firefox uses the `~/.mailcap` file. But this file is not whitelisted by the `firefox` profile. Adding ``` whitelist ${HOME}/.mailcap ``` in `firefox-common.local` solves this problem. So this is what should be done in the official profile. ### Environment - Name/version/arch of the Linux kernel (`uname -srm`): Linux 6.16.3+deb14-amd64 x86_64 - Name/version of the Linux distribution (e.g. "Ubuntu 20.04" or "Arch Linux"): Debian/unstable - Name/version of the relevant program(s)/package(s) (e.g. "firefox 134.0-1, mesa 1:24.3.3-2"): Firefox since at least version 119 (and Nightly affected too) - Version of Firejail (`firejail --version`): 0.9.76 ### Checklist - [x] The issues is caused by firejail (i.e. running the program by path (e.g. `/usr/bin/vlc`) "fixes" it). - [x] I can reproduce the issue without custom modifications (e.g. globals.local). - [x] The program has a profile. (If not, request one in `https://github.com/netblue30/firejail/issues/1139`) - [x] The profile (and redirect profile if exists) hasn't already been fixed [upstream](https://github.com/netblue30/firejail/tree/master/etc). - [x] I have performed a short search for similar issues (to avoid opening a duplicate). - [x] I'm aware of `browser-allow-drm yes`/`browser-disable-u2f no` in `firejail.config` to allow DRM/U2F in browsers. - [x] I used `--profile=PROFILENAME` to set the right profile. (Only relevant for AppImages)

gitea-mirror

2026-05-05 09:58:14 -06:00

closed this issue
added the
bug
label

gitea-mirror referenced this issue

2026-05-05 10:25:53 -06:00

[PR #3406] [MERGED] DBus filtering enhancements #4751

No milestone

No project

No assignees

1 participant

Notifications

Due date

The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set.

Reference: github-starred/firejail#3408

No description provided.

Rows
Columns