Buffer overflow in Neovim
CVE-2026-25749
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.
Vulnerability class: Buffer Overflow
EPSS: 0.002 (11.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.6 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:H.
Affected products
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Patch, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-25749?
- CVE-2026-25749 is a medium-severity vulnerability in Neovim, classified under Heap-based Buffer Overflow. CVSS score: 6.6/10. Published 2026-02-06.
- How severe is CVE-2026-25749?
- Medium severity. CVSS v3 base score is 6.6 out of 10.