Bug 2487989 (CVE-2026-52859)

Summary: CVE-2026-52859 vim: Vim: Denial of Service via out-of-bounds write in terminal handling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Vim, an open-source command-line text editor. This vulnerability allows a program displaying output in a Vim terminal window to trigger an out-of-bounds write by sending a specific byte sequence. This can lead to a crash of the Vim application, resulting in a Denial of Service (DoS) for the user.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2488267    
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Description OSIDB Bzimport 2026-06-11 19:02:47 UTC 
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.