CVE-2025-26603: Vim is a greatly improved version of the good old UNIX editor Vi.

Vim is a greatly improved version of the good old UNIX editor Vi.

Vim is a greatly improved version of the good old UNIX editor Vi. Vim allows to redirect screen messages using the `:redir` ex command to register, variables and files. It also allows to show the contents of registers using the `:registers` or `:display` ex command. When redirecting the output of `:display` to a register, Vim will free the register content before storing the new content in the register. Now when redirecting the `:display` command to a register that is being displayed, Vim will free the content while shortly afterwards trying to access it, which leads to a use-after-free. Vim pre 9.1.1115 checks in the ex_display() function, that it does not try to redirect to a register while displaying this register at the same time. However this check is not complete, and so Vim does not check the `+` and `*` registers (which typically donate the X11/clipboard registers, and when a clipboard connection is not possible will fall back to use register 0 instead. In Patch 9.1.1115 Vim will therefore skip outputting to register zero when trying to redirect to the clipboard registers `*` or `+`. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Description from the National Vulnerability Database, published by GitHub

What it means for a small business

If your business uses vim, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.24%, higher than 15% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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