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Mallory
High

Vim modeline sandbox bypass arbitrary OS command execution

IdentifiersCVE-2026-34982CWE-78· Improper Neutralization of Special…

CVE-2026-34982 is a high-severity vulnerability in Vim affecting versions prior to 9.2.0276. The flaw is a modeline sandbox bypass that allows arbitrary OS command execution when a user opens a specially crafted file in Vim. According to the provided content, the root cause is that the complete, guitabtooltip, and printheader options are missing the P_MLE flag, which allows them to be set from a modeline when they should be restricted. In addition, the mapset() function lacks a check_secure() call, allowing it to be abused from sandboxed expressions. The complete option is specifically noted as accepting F{func} syntax for completion callbacks and lacking both P_SECURE and P_MLE, enabling arbitrary lambda expressions to be accepted from modelines. Together, these issues permit bypass of Vim's intended modeline sandbox protections and can be chained into OS command execution.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an attacker to execute arbitrary operating system commands with the privileges of the user running Vim. This can compromise the victim's workstation or development environment, with high impact to confidentiality and integrity. The attack is particularly relevant in developer workflows because Vim is commonly used to open untrusted source code and text files across Linux distributions and development environments.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, disable modeline processing in Vim by adding set nomodeline to the user's .vimrc. More generally, avoid opening untrusted files in vulnerable Vim versions until the update is applied.

Remediation

Patch, then assume compromise.

Upgrade Vim to version 9.2.0276 or later. The fix in patch 9.2.0276 adds the missing security restrictions for the affected options and enforces proper secure-access checks, including addressing the missing check_secure() protection in mapset().
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
Rocky LinuxRocky Linuxoperating_system
VimVimapplication

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What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity7

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