Besides the early fallout of switching to Rust Coreutils on Ubuntu 25.10 causing some breakage, a more pressing issue has been discovered: Ubuntu 25.10’s unattended upgrades functionality for automatic security updates is currently broken due to a Rust Coreutils bug.
Earlier this month it was reported that the date -r command can report the wrong date on Ubuntu 25.10 due to a Rust Coreutils difference compared to GNU Coreutils. It was noted that this could cause issues for backup scripts and other software relying on the “date -r” output and behavior being the same as GNU Coreutils.
Last week by an Ubuntu developer it was initially decided it wasn’t all too pressing:
“This is fixed upstream in 88a7fa7adfa048dabdffc99451d7aba1d9e6a9b6 and we can pull this in at a later point in time. For the time being, we’ll focus on fixing critical issues that could introduce unsafety further down the chain, such as the short writes in bug 2125535.
I do not anticipate there are a lot of shell “monitoring” scripts, particularly in 25.10, as this is not an LTS release. For the upcoming LTS release this of course is a higher priority item given more enterprise use cases.”
But now it’s been realized that this regression ends up breaking Ubuntu’s own unattended-upgrades functionality on Ubuntu 25.10.
It was reported earlier today on this bug breaking unattended upgrades:
“This bug breaks unattended upgrades in 25.10! apt.systemd.daily checks if the modification date of the timestamp file /var/lib/apt/periodic/upgrade-stamp is older than the current date minus an interval. The difference is always seen as 0 and unattended upgrades never run. Ouch 🙁 I now created #2129660.”
In turn this bug report was now raised to “Critical” importance as a public security issue.
There is now this bug report as well specifically around unattended upgrades being broken. A fixed version of Rust Coreutils is being worked on and currently in the proposed archive. Once that rust-coreutils update is available in the main archive, users will need to manually update their Ubuntu 25.10 systems first to get that package before the unattended upgrades will work again:
“Users will need to manually run `apt update` to make the updated lists available to unattended-upgrades, and may manually upgrade with `apt upgrade`. We will provide further information once the update is released.”
At least this was spotted in Ubuntu 25.10 and ahead of the important Ubuntu 26.04 LTS cycle…
