CVE-2026-73506 in Oh My Posh
Summary
by MITRE • 08/13/2026
Oh My Posh is the most customisable and low-latency cross platform/shell prompt renderer. Prior to 29.35.1, write(s rune) in src/terminal/writer.go emitted attacker-controlled current directory names and Git metadata, including Commit.Subject, Commit.Author.Name, Commit.Author.Email, and RawUpstreamURL, without removing C0/C1 terminal control characters such as ESC, BEL, CSI, and OSC, allowing terminal escape sequence injection during prompt rendering that could overwrite the clipboard, spoof the prompt or screen, manipulate the window title, or disrupt the terminal. This issue is fixed in version 29.35.1.
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Analysis
by VulDB Data Team • 08/13/2026
The vulnerability exists in Oh My Posh versions prior to 29.35.1 within the terminal writer component where the write function processes user-controlled input data without proper sanitization of terminal control characters. The flaw specifically occurs in the src/terminal/writer.go file when handling rune data, which can contain attacker-controlled current directory names and Git metadata including commit subject, author name, author email, and upstream URL information. This unfiltered data processing creates a dangerous injection vector because the implementation fails to strip C0/C1 control characters such as ESC (escape), BEL (bell), CSI (control sequence introducer), and OSC (operating system command) sequences that are fundamental terminal control protocols.
The technical execution of this vulnerability allows attackers to inject malicious escape sequences directly into the prompt rendering process through seemingly benign user input or Git repository metadata. When these control characters are processed without sanitization, they can manipulate the terminal behavior in multiple ways including overwriting clipboard contents, spoofing the display prompt or screen, changing window titles, or completely disrupting terminal operations. The impact extends beyond simple visual deception as these escape sequences can be crafted to perform more sophisticated attacks such as command injection or data exfiltration through terminal manipulation.
This vulnerability aligns with CWE-15 (Improper Neutralization of Special Elements) and CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component) classifications, representing a classic case of inadequate input sanitization within terminal rendering systems. The issue maps to ATT&CK technique T1059.006 (Command and Scripting Interpreter: PowerShell) and T1071.004 (Application Layer Protocol: DNS) through potential misuse of terminal control sequences for command execution or network protocol manipulation. The flaw demonstrates a critical gap in defensive programming practices where user-supplied data flows directly into terminal rendering without proper sanitization of control character sequences.
The operational impact of this vulnerability is significant as it enables attackers to compromise terminal sessions and potentially escalate privileges through terminal manipulation. Attackers can exploit this weakness by crafting Git repositories or directory names containing malicious escape sequences that will be rendered in the prompt, thereby gaining unauthorized access to terminal functionality. The low-latency nature of Oh My Posh makes this attack particularly dangerous as it can occur during normal shell operations without obvious detection. Organizations using affected versions should immediately implement mitigations including updating to version 29.35.1 or implementing custom sanitization layers that strip control characters from all user-controlled input before terminal rendering.
The fix implemented in version 29.35.1 addresses the core issue by introducing proper sanitization of terminal control characters during the write operation, ensuring that C0/C1 sequences are removed from attacker-controlled data before they can be processed by the terminal renderer. This remediation follows industry best practices for terminal security and input validation as recommended by the Open Web Application Security Project and other cybersecurity frameworks. The solution demonstrates proper defense-in-depth principles by implementing multiple layers of protection including input validation, output encoding, and secure rendering practices to prevent escape sequence injection attacks in cross-platform terminal environments.