CVE-2026-59857 Vim: Out-of-bounds Write in SAL Soundfolding
A boundary error in Vim's spell checker allows a stack buffer overflow, potentially crashing the editor when processing specific words with SAL rules.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-59857?
CVE-2026-59857 is a medium-severity memory corruption vulnerability in Vim Vim, published on 9 Jul 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-787
Which versions are affected by CVE-2026-59857?
It affects 1 product.
Products include Vim Vim.
How do I fix CVE-2026-59857?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-59857 being exploited?
There is no known exploitation of CVE-2026-59857 in the wild and no public exploit code.
Other vulnerabilities in Vim Vim
Sources
Also known as ALPINE-CVE-2026-59857, BELL-CVE-2026-59857, CLSA-2026-1784189693, CLSA-2026-1784800448, DEBIAN-CVE-2026-59857, ECHO-835b-eaa6-823f and 3 more.