#1108642 chromium: potentially serious security bug

Package:
chromium
Source:
chromium
Description:
web browser
Submitter:
Fourhundred Thecat
Date:
2025-10-08 11:31:02 UTC
Severity:
normal
Tags:
#1108642#5
Date:
2025-07-02 07:27:34 UTC
From:
To:
I am experiencing very weird and suspicious issue on debian 12.

For context, I am using grsecurity + RBAC, which gives me the
possibility to see what files each program wants to access. My issue is
not caused by RBAC. but RBAC brought my attention to this issue.

SO, I have upgraded chromium browser to: 138.0.7204.49

and suddenly when chromium starts, in addition to trying to access the
usual files in my home, such as ~/.config/chromium or ~/.cache , it now
tries to access sensitive folders on my system:

~/.ssh/
~/.gnupg/
~/.dbus/
/boot/

(while ~/.dbus is not as immediately alarming as the others, Chromium
accessing this when it didn't before is still a change in behavior that
deserves scrutiny)

this never happened before. I am sure, because the RBAC rules that I am
using would have alerted me.

this is highly suspicious and potentially a serious security issue !

#1108642#8
Date:
2025-07-02 15:37:12 UTC
From:
To:
Hi,

Thanks for the report. Please run chromium under strace so that we can
see what it's doing, and send it here. Eg, `strace -f --trace=openat
chromium &>  c138.log`

Thanks,
Andres

#1108642#15
Date:
2025-09-10 10:58:39 UTC
From:
To:
originally, I have reported this issue on chromium 138.0.7204.49-1~deb12u1

the problem got fixed by upgrading chromium to next version

but now, after upgrading to
Version 140.0.7339.80 the problem is back:

here is my RBAC reporting chromium trying to open files that it has no
business opening:


07:13:43  grsec: (testuser:U:/usr/lib/chromium/chromium) denied access
to hidden file /home/testuser/.ssh by
/usr/lib/chromium/chromium[ThreadPoolForeg:7646] uid/euid:1000/1000
gid/egid:1000/1000, parent /usr/sbin/init[init:1] uid/euid:0/0 gid/egid:0/0
07:13:43  grsec: (testuser:U:/usr/lib/chromium/chromium) denied access
to hidden file /home/testuser/.gnupg by
/usr/lib/chromium/chromium[ThreadPoolForeg:7646] uid/euid:1000/1000
gid/egid:1000/1000, parent /usr/sbin/init[init:1] uid/euid:0/0 gid/egid:0/0
07:13:43  grsec: (testuser:U:/usr/lib/chromium/chromium) denied access
to hidden file /boot by /usr/lib/chromium/chromium[ThreadPoolForeg:7646]
uid/euid:1000/1000 gid/egid:1000/1000, parent /usr/sbin/init[init:1]
uid/euid:0/0 gid/egid:0/0
07:13:43  grsec: (testuser:U:/usr/lib/chromium/chromium) denied access
to hidden file /home/testuser/.dbus by
/usr/lib/chromium/chromium[ThreadPoolForeg:7646] uid/euid:1000/1000
gid/egid:1000/1000, parent /usr/sbin/init[init:1] uid/euid:0/0 gid/egid:0/0

why is chromium doing this, and why does Debian tolerate this behavior ?

#1108642#20
Date:
2025-10-05 21:01:39 UTC
From:
To:
Control: tags -1 + moreinfo

As I said, it would be helpful if you could send an strace to show
exactly what's attempting to be opened. Chromium specifically has code
to disallow access to special directories, but recent changes to
optimize the blocklist (
https://chromium.googlesource.com/chromium/src/+/e067077375020cf7c7cd1b27cee529e8db5f6ce3%5E%21/
,
https://chromium.googlesource.com/chromium/src/+/37141c231485b178e8d9a6064916a1016311f207%5E%21/
) may have made it so that it first queries those directories for
existence before adding them to the blocklist (or similar unintended
consequences).

#1108642#25
Date:
2025-10-08 11:21:58 UTC
From:
To:
thanks for the update.

the troubleshooting you suggest would require me to run chromium with
strace and let it have unrestricted access to my sensitive data
I would have to set up some testing laptop for that,  asI don't want to
do it on my main laptop and risk having my life ssh and gpg keys compromised

I hoped it would be enough to report this weird behavior, and the
maintainers / developers can run these tests themselves, as they are
surely better equipped for that than I am