CVE-2026-55693 Vim: Out-of-bounds Write in Spell File Word Count
A crafted spell file can cause an out-of-bounds write in Vim, leading to a crash or potential code execution when spell suggestions are used.
- 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-2026-55693?
CVE-2026-55693 is a medium-severity memory corruption vulnerability in Vim Vim, published on 25 Jun 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 9.2.0653, the tree_count_words() function in src/spellfile.c fills in the word-count fields of a spell-file word trie by walking it iteratively with a depth counter. The counter is bounded only by the trie structure itself; it is never checked against the size of the fixed MAXWLEN-element stack arrays it indexes (arridx[], curi[], wordcount[]). A crafted .spl/.sug file pair, loaded when the user invokes spell suggestion, can drive the descent arbitrarily deep, so the function writes past the end of those arrays. This is a stack out-of-bounds write that corrupts the call frame and crashes the editor. This vulnerability is fixed in 9.2.0653.
Weakness: CWE-787
Which versions are affected by CVE-2026-55693?
It affects 1 product.
Products include Vim Vim.
How do I fix CVE-2026-55693?
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-2026-55693 being exploited?
There is no known exploitation of CVE-2026-55693 in the wild and no public exploit code.
Other vulnerabilities in Vim Vim
Sources
Also known as AZL-91107, BELL-CVE-2026-55693, DEBIAN-CVE-2026-55693, ECHO-31d3-7c0e-c6d2, GHSA-wgh4-64f7-q3jq, MINI-83vm-2w88-v66c and 3 more.