CVE-2026-55892
Description
A flaw was found in Vim, an open-source command-line text editor. A remote attacker could exploit this vulnerability by convincing a user to load a specially crafted spell file. This malicious file can trigger a stack out-of-bounds write, which corrupts the editor's memory and causes it to crash. This leads to a Denial of Service (DoS), making the editor unavailable to the user.
Statement
A flaw was found in Vim's spell file handling. The dump_prefixes() function in src/spell.c does not validate the depth of the prefix trie against the size of fixed-size stack arrays, allowing a crafted .spl file to cause a stack out-of-bounds write and crash. Red Hat ships Vim in all RHEL versions and OpenShift CoreOS. Exploitation requires a user to load a malicious spell file and run :spelldump or spelling completion.
Mitigation
Do not load untrusted spell files (.spl) from unknown sources. Avoid using :spelldump with spell files of unknown provenance.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 5.5 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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