Heap Buffer Overflow Vulnerability in Vim Text Editor

CVE-2026-45130

What is CVE-2026-45130?

Vim is an open-source command line text editor that is susceptible to a heap buffer overflow vulnerability prior to version 9.2.0450. This vulnerability arises in the read_compound() function of src/spellfile.c when handling specially crafted spell files (.spl) with UTF-8 encoding enabled. An attacker can exploit this weakness through a manipulated length field in the compound section of a spell file, which overflows a 32-bit signed integer multiplication. This overflow leads to an inadequate buffer allocation during a write loop, eventually compromising the heap. Given that the 'spelllang' option can be influenced by a modeline in text files, a maliciously crafted .spl file can be triggered from a modeline if it is placed on the runtime path. Update to version 9.2.0450 or later to mitigate this issue.

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