Description

powerlevel10k fails to neutralize control characters in the package.json version field when rendering the package prompt segment. Attackers can inject raw escape bytes in the version string to emit arbitrary terminal control sequences on each prompt render when the shell enters affected directories.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "3.3",
  "pubDate": "2026-08-17T21:16:57.930Z",
  "pubdate": "2026-08-17T21:16:57.930Z",
  "executiveSummary": "A terminal control sequence injection vulnerability has been identified within the powerlevel10k shell theme. The flaw specifically resides in the package prompt segment, which fails to properly neutralize or sanitize control characters present within the version field of a parsed package.json file.\nThis security deficiency allows malicious threat actors to embed raw escape bytes directly into the version string of a local package.json configuration file. Consequently, when a victim navigates into a directory containing the maliciously crafted file using an affected shell environment, the prompt rendering mechanism processes and outputs the unescaped control characters.\nThe primary impact of this vulnerability involves the emission of arbitrary terminal control sequences. Depending on the terminal emulator and capabilities utilized, an attacker could manipulate terminal behavior, execute unintended command sequences via carriage return or injection techniques, or mislead users by spoofing terminal output. Exploitation requires local file system control or the ability to trick a user into cloning or downloading a repository containing the malicious package.json payload. No authentication or elevated privileges are required beyond standard read access to the directory structure, shifting the risk profile toward targeted developer environments and malicious repository distribution.",
  "technicalDetails": "The vulnerability stems from inadequate input validation and sanitization within the powerlevel10k package prompt segment when extracting and rendering metadata from a package.json file. Specifically, the component processes the version field without stripping, encoding, or neutralizing raw escape bytes and terminal control characters.\nThe vulnerable component is the package prompt segment parsing logic within powerlevel10k responsible for reading and displaying Node.js project metadata. Affected versions include any deployment utilizing the unpatched package segment logic where raw string interpolation of the version property occurs directly into the active terminal stream during prompt generation.\nThe attack flow proceeds as follows: First, an attacker crafts or modifies a package.json file, inserting raw ANSI escape sequences, control bytes (such as ESC, '\u001b'), or other terminal manipulation characters into the version attribute. Second, the victim navigates into the directory containing this file using a shell configured with the powerlevel10k prompt. Third, upon entering the directory, the shell evaluates the prompt configuration, triggering the powerlevel10k package prompt segment to read the package.json version field. Fourth, the theme renders the segment by echoing the raw string content directly to standard output without prior sanitization.\nBecause the terminal emulator interprets the injected escape bytes as control commands rather than literal text characters, the embedded payload executes immediately upon rendering. Depending on the injected payload, this can result in cursor repositioning, text clearing, color alteration, or the potential injection of simulated keyboard input if the terminal emulator supports advanced escape sequences and vulnerable configurations are present.\nThe vulnerability does not require network exposure, as it is entirely localized to the local file system and prompt rendering process. Furthermore, no specialized authentication or elevated privileges are necessary; any local user or automated script that parses the directory triggers the insecure rendering behavior."
}