Linux

cross-posted from: https://lemmy.world/post/46310733

Cybersecurity researchers have disclosed details of a Linux local privilege escalation (LPE) flaw that could allow an unprivileged local user to obtain root.

The high-severity vulnerability tracked as CVE-2026-31431 (CVSS score: 7.8) has been codenamed Copy Fail by Xint.io and Theori.

"An unprivileged local user can write four controlled bytes into the page cache of any readable file on a Linux system, and use that to gain root," the vulnerability research team at Xint.io and Theori said.

At its core, the vulnerability stems from a logic flaw in the Linux kernel's cryptographic subsystem, specifically within the algif_aead module. The issue was introduced in a source code commit made in August 2017.

Successful exploitation of the shortcoming could allow a simple 732-byte Python script to edit a setuid binary and obtain root on essentially all Linux distributions shipped since 2017, including Amazon Linux, RHEL, SUSE, and Ubuntu. The Python exploit involves four steps -

• Open an AF_ALG socket and bind to authencesn(hmac(sha256),cbc(aes))
• Construct the shellcode payload
• Trigger the write operation to the kernel's cached copy of "/usr/bin/su"
• Call execve("/usr/bin/su") to load the injected shellcode and run it as root

While the vulnerability is not remotely exploitable in isolation, a local unprivileged user can get root simply by corrupting the page cache of a setuid binary. The same primitive also has cross-container impacts as the page cache is shared across all processes on a system.

Clem talks about that in the comments. What are some no hassle, Debian based, rustless distros as alternative to Mint?

On my system, I wanted Firefox profiles to feel like their own browser instances. Meaning, their own app icons and to not be grouped together. Almost like how it is on MacOS.

To do this, I had to make multiple .desktop files. Here are the contents of that file. This targets flatpak, but it should work for traditional Firefox installs too.

I called this profile "Personal". Note that this says --profile "/home/USERNAME/.var/app/org.mozilla.firefox/config/mozilla/firefox/personal". In this, "personal" is a symlink to the real profile folder name located in the same directory.

[Desktop Entry]
Version=1.0
Type=Application
Exec=/usr/bin/flatpak run >--env=MOZ_APP_REMOTINGNAME=Personal >--branch=stable --arch=x86_64 --command=firefox >--file-forwarding org.mozilla.firefox --profile "/home/USERNAME/.var/app/org.mozilla.firefox/config/mozilla/firefox/personal" --name org.mozilla.firefox.Personal >--class org.mozilla.firefox.Personal @@u %u @@
Terminal=false
X-MultipleArgs=false
Icon=/home/USERNAME/.local/share/icons/firefox-heart.png
StartupWMClass=org.mozilla.firefox.Personal
DBusActivatable=false
Categories=GNOME;GTK;Network;WebBrowser;
MimeType=application/json;application/pdf;application/rdf+xml;application/rss+xml;application/x-xpinstall;application/xhtml+xml;application/xml;audio/flac;audio/ogg;audio/webm;image/avif;image/gif;image/jpeg;image/png;image/svg+xml;image/webp;text/html;text/xml;video/ogg;video/webm;x-scheme-handler/chrome;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/mailto;
StartupNotify=true
Actions=new-window;new-private-window;
Name=Firefox (Personal)
Comment=Fast and private browser
GenericName=Web Browser
Keywords=Internet;WWW;Browser;Web;Explorer;
X-GNOME-FullName=Mozilla Firefox

[Desktop Action new-window]
Exec=/usr/bin/flatpak run >--env=MOZ_APP_REMOTINGNAME=Personal >--branch=stable --arch=x86_64 --command=firefox >--file-forwarding org.mozilla.firefox --profile "/home/USERNAME/.var/app/org.mozilla.firefox/config/mozilla/firefox/personal" --name org.mozilla.firefox.Personal >--class org.mozilla.firefox.Personal --new-window @@u %u @@
Name=New Window

[Desktop Action new-private-window]
Exec=/usr/bin/flatpak run >--env=MOZ_APP_REMOTINGNAME=Personal >--branch=stable --arch=x86_64 --command=firefox >--file-forwarding org.mozilla.firefox --profile "/home/USERNAME/.var/app/org.mozilla.firefox/config/mozilla/firefox/personal" --name org.mozilla.firefox.Personal --class org.mozilla.firefox.Personal --private-window @@u %u @@
Name=New Private Window

OC by @novafunc@discuss.tchncs.de

edit: oh this is fun. https://thecybersecguru.com/news/massive-attack-ubuntu-canonical-313-team-extortion/

woaw

also a good blog post about it https://xint.io/blog/copy-fail-linux-distributions