CVE-2026-59856
Description
A flaw was found in Vim, an open-source command-line text editor. The PHP omni-completion script improperly handles specially crafted input. When a victim opens a malicious PHP file and invokes omni-completion, an unescaped class or trait name can be interpreted as Ex commands. This allows a remote attacker to achieve arbitrary operating-system command execution.
Statement
Red Hat Product Security has rated this vulnerability as having a Moderate impact. While successful exploitation allows for arbitrary operating-system command execution when a user opens a crafted PHP file and triggers omni-completion, this feature is disabled by default in Red Hat products. The requirement for a non-default configuration, combined with mandatory user interaction, significantly reduces the real-world risk."
Mitigation
Users should exercise caution when opening untrusted PHP files and avoid invoking omni-completion on them. To prevent exploitation, the PHP omni-completion script can be disabled by moving or renaming `phpcomplete.vim`. For example, execute `mv /usr/share/vim/vim*/autoload/phpcomplete.vim /usr/share/vim/vim*/autoload/phpcomplete.vim.bak`. This action will disable PHP omni-completion functionality. A restart of Vim is necessary for this change to take effect.
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 | 5.3 | 7.8 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | High | N/A |
| Integrity Impact | Low | High | N/A |
| Availability Impact | Low | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
In some cases, injectable code controls authentication; this may lead to a remote vulnerability.
Access Control
Technical Impact: Gain Privileges or Assume Identity
Injected code can access resources that the attacker is directly prevented from accessing.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
When a product allows a user's input to contain code syntax, it might be possible for an attacker to craft the code in such a way that it will alter the intended control flow of the product. As a result, code injection can often result in the execution of arbitrary code. Code injection attacks can also lead to loss of data integrity in nearly all cases, since the control-plane data injected is always incidental to data recall or writing.
Non-Repudiation
Technical Impact: Hide Activities
Often the actions performed by injected control code are unlogged.
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