#1121748 firefox 140.3 esr crashes during startup on Debian 12.12

Package:
firefox-esr
Source:
firefox-esr
Description:
Mozilla Firefox web browser - Extended Support Release (ESR)
Submitter:
Thinker Lee
Date:
2025-12-01 19:41:02 UTC
Severity:
normal
#1121748#5
Date:
2025-12-01 19:38:08 UTC
From:
To:
Recently, we (Firefox) have received a lot crash reports [1] of firefox
140.5.0 esr on Debian 12.12 (bookworm).
The number of crash reports with the same stacktrace signature
started rising dramatically since Sep 18 less than 2 weeks after the
release date of Debian 12.12.
The issue relates to |setenv|/|getenv| with multi-threading. Libraries
or graphics drivers may call |getenv|/|setenv|
without synchronization. |setenv| may reallocate the buffer pointed by
the global variable|environ| while |getenv|
on another thread is reading the buffer. It obviously can cause an
use-after-free error.
GNU C library has a flag to turn on a thread-safe protection for
|getenv|/|setenv|, however, not every distro turn it on.

I am wondering if any changes of Debian 12.12 raise the number of crashes.
We need your help to identify what happens on Debian 12.12 devices
causing it.

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1993100