Buffer overflow in Vim

CVE-2026-59857

Vim is an open source, command line text editor. Prior to 9.2.0725, the single-byte branch of spell_soundfold_sal() in src/spell.c translates a word through a spell file's SAL sound-folding rules into a caller-owned result buffer, but its result writes are guarded with reslen < MAXWLEN, allowing reslen to reach MAXWLEN before res[reslen] = NUL writes one byte past the end of the MAXWLEN-element stack buffer. A boundary-length word passed to soundfold(), or reached via sound-based spell suggestion while a SAL-based spell language is active under a non-multibyte 8-bit encoding, can corrupt the eval_soundfold() stack frame and crash the editor. This issue is fixed in version 9.2.0725.

Vulnerability class: Buffer Overflow

EPSS: 0.001 (1.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

Affected products

  • Vim — versions < 9.2.0725

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-59857?
CVE-2026-59857 is a medium-severity vulnerability in Vim, classified under Out-of-bounds Write. CVSS score: 5.5/10. Published 2026-07-09.
How severe is CVE-2026-59857?
Medium severity. CVSS v3 base score is 5.5 out of 10.