Out-of-bounds write in Vim - CVE-2026-55693

Vulnerability identifier: #VU134580

CSH Severity: Medium

CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-55693

CWE-ID: CWE-787

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to out-of-bounds write in the tree_count_words() function in src/spellfile.c when parsing a crafted .spl/.sug spell file pair during spell suggestion loading. A remote attacker can supply a specially crafted spell file pair to cause a denial of service.

User interaction is required: spell checking must be enabled and the user must invoke spell suggestion on a misspelled word.

Vim
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Ubuntu
openEuler
vim (Ubuntu package)
vim (Red Hat package)
vim-filesystem
vim-minimal
vim-enhanced
vim-debugsource
vim-debuginfo
vim-common
vim-X11
vim

Install security update from vendor's website.

Vim - update to 9.2.0653
vim (Ubuntu package) - addressed in versions 2:7.4.052-1ubuntu3.1+esm30, 2:7.4.1689-3ubuntu1.5+esm36, 2:8.0.1453-1ubuntu1.13+esm21, 2:8.1.2269-1ubuntu5.32+esm9, 2:8.2.3995-1ubuntu2.33, 2:9.1.0016-1ubuntu7.17, 2:9.1.0967-1ubuntu6.8, 2:9.1.2141-1ubuntu4.6
vim (Red Hat package) - addressed in versions 8.0.1763-31.el8_10, 8.2.2637-26.el9_8.13
vim-filesystem - addressed in versions 9.0-51, 9.0.2092-37
vim-minimal - addressed in versions 9.0-51, 9.0.2092-37
vim-enhanced - addressed in versions 9.0-51, 9.0.2092-37
vim-debugsource - addressed in versions 9.0-51, 9.0.2092-37
vim-debuginfo - addressed in versions 9.0-51, 9.0.2092-37
vim-common - addressed in versions 9.0-51, 9.0.2092-37
vim-X11 - addressed in versions 9.0-51, 9.0.2092-37
vim - addressed in versions 9.0-51, 9.0.2092-37

• https://github.com/vim/vim/security/advisories/GHSA-wgh4-64f7-q3jq
• https://github.com/vim/vim/commit/a80874d9b84a01040e3d1aef2d4a59e1934dafb7

• Out-of-bounds write in Vim
• Ubuntu update for vim
• openEuler 22.03 LTS SP4 update for vim
• openEuler 24.03 LTS SP1 update for vim
• openEuler 20.03 LTS SP4 update for vim
• openEuler 24.03 LTS SP3 update for vim
• Red Hat Enterprise Linux 8 update for vim
• Red Hat Enterprise Linux 9 update for vim