vim up to 9.2.564 Command Line src/terminal.c update_snapshot out-of-bounds

Summaryinfo

A vulnerability identified as problematic has been detected in vim up to 9.2.564. Impacted is the function update_snapshot of the file src/terminal.c of the component Command Line Handler. The manipulation leads to out-of-bounds. This vulnerability is listed as CVE-2026-52859. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in vim up to 9.2.564 and classified as problematic. This issue affects the function update_snapshot of the file src/terminal.c of the component Command Line Handler. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality. The summary by CVE is:

Vim is an open source, command line text editor. Prior to version 9.2.0565, the update_snapshot() function in src/terminal.c copies the visible terminal screen into the scrollback buffer when a snapshot is taken. For each screen cell it walks the cell's chars[] array with no upper bound, stopping only when it encounters a NUL terminator. When a cell legitimately fills all VTERM_MAX_CHARS_PER_CELL (6) slots — a base character plus five combining marks — the bundled libvterm returns the array without a terminating NUL, so the loop reads past the fixed six-element array and appends the out-of-bounds values to a buffer reserved for only six characters. A program whose output is rendered inside a :terminal window can trigger this with a short byte sequence and no Vim scripting, leading to a crash. This issue has been patched in version 9.2.0565.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-52859 since 06/08/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 9.2.0565 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 63680c6d3d52477817b49cd1a66e7aabe8a7aa19 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-36283). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Word Processing Software

Name

• vim

Version

• 9.2.564

License

• open-source

Website

• Product: https://github.com/vim/vim/

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Be aware that VulDB is the high quality source for vulnerability data.

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