CVE-2026-25749: neovim Heap-based Buffer Overflow

Vulnerability summary

CVE-2026-25749 is a medium (CVSS 6.6) Heap-based Buffer Overflow vulnerability in neovim. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 11.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 06-02-2026
   PublishedVulnerability first disclosed.
2. 09-02-2026
   Last modifiedVulnerability information updated.

Description

Vim is an open source, command line text editor. Prior to version 9.1.2132, a heap buffer overflow vulnerability exists in Vim's tag file resolution logic when processing the 'helpfile' option. The vulnerability is located in the get_tagfname() function in src/tag.c. When processing help file tags, Vim copies the user-controlled 'helpfile' option value into a fixed-size heap buffer of MAXPATHL + 1 bytes (typically 4097 bytes) using an unsafe STRCPY() operation without any bounds checking. This issue has been patched in version 9.1.2132.

• CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().