CVE-2025-26603: vim Use-After-Free — Fix

Description

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.

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CVSS v3.1 Score

4.2

MEDIUM

CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor	Product	Versions
vim	vim	< 9.1.1115
netapp	hci_compute_node	All

References

Advisories & Patches

https://github.com/vim/vim/commit/c0f0e2380e5954f4a52a131bf6b8 https://github.com/vim/vim/security/advisories/GHSA-63p5-mwg2-787v

Other References

https://security.netapp.com/advisory/ntap-20250306-0003/

Frequently Asked Questions

What is CVE-2025-26603? +

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. It has a CVSS v3.1 base score of 4.2 (MEDIUM).

How severe is CVE-2025-26603? +

CVE-2025-26603 has a CVSS v3.1 score of 4.2 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-26603? +

CVE-2025-26603 affects products from netapp, vim, specifically: hci_compute_node, vim. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-26603? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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