high CVSS 7.8

CVE-2026-57456·Python vulnerability

Vim is an open source, command line text editor. Prior to 9.2.0699, Vim's Python omni-completion (runtime/autoload/python3complete.vim and the legacy pythoncomplete.vim) executes reconstructed function and class definitions from the current buffer with exec() as part of populating the completion dictionary. When reconstructing that source, each scope's docstring is inserted verbatim between triple quotes with no escaping, so a hostile buffer can break out of the triple-quoted literal and execute attacker-controlled Python during omni-completion. This vulnerability is fixed in 9.2.0699.

Severity
high
Software
Python
Fixed in
9.2.0699
Published
2026-06-25

Affected versions

Until: 9.2.0699

Fixed in: 9.2.0699

How to fix this CVE

Update Vim to version 9.2.0699 or later to patch the Python omni-completion vulnerability that allows arbitrary code execution through malicious docstrings. The vulnerability exists in Vim's Python completion feature, which improperly escapes docstrings when reconstructing function definitions, enabling attackers to break out of triple-quoted literals and execute Python code. Ensure your system package manager is updated and Vim is reinstalled or upgraded immediately.

sudo dnf update vim

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check Vim version with `vim --version | head -1` and verify it is 9.2.0699 or later
  2. Step 2: Confirm Python omni-completion is enabled by checking if `~/.vim/autoload/python3complete.vim` or `runtime/autoload/python3complete.vim` exists and contains exec() calls
  3. Step 3: Search shell history and application logs for patterns like `python3complete.vim` being invoked during file editing sessions: `grep -r 'python3complete' /var/log/ ~/.vim/`
  4. Step 4: After patching, re-run `vim --version` and verify the build date is after the 9.2.0699 release; test omni-completion on a benign Python file with Ctrl+X Ctrl+O to ensure functionality

FAQ

What is CVE-2026-57456?

This vulnerability affects Vim's Python omni-completion feature, which reconstructs Python code definitions from the current buffer using exec(). Attackers can craft malicious docstrings that break out of triple-quoted literals to execute arbitrary Python code when users trigger autocompletion.

Is CVE-2026-57456 being actively exploited?

No, this vulnerability is not currently listed in CISA's Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available, though the attack vector is straightforward and patches should be applied proactively.

What versions of Vim are affected by CVE-2026-57456?

All versions of Vim prior to 9.2.0699 are vulnerable; the fix was released in version 9.2.0699 and later.

How do I check if my server is vulnerable to CVE-2026-57456?

Run `vim --version | head -1` to display your Vim version; if it shows a version lower than 9.2.0699, your system is vulnerable. Additionally, check if Python support is compiled in with `vim --version | grep +python3`.

Does Defensia detect CVE-2026-57456?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Vim is installed on a monitored server, CVE-2026-57456 will appear in your dashboard with remediation steps.

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References

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