Vulnerability Database

363,159

Total vulnerabilities in the database

Oh My Posh: Terminal escape sequence injection via unsanitized prompt segment data — github.com/jandedobbeleer/oh-my-posh

Improper Neutralization of Escape, Meta, or Control Sequences

Summary

Oh My Posh renders dynamic, potentially attacker-controlled strings (the current directory name, Git commit metadata, environment variable values, command output) into the prompt without neutralizing raw terminal control characters. An attacker who controls one of these values can inject ANSI/OSC escape sequences that the victim's terminal executes on every prompt render. (This is separate from the path-segment command-execution report; it has a different root cause and fix.)

Details

src/terminal/writer.go, write(s rune): the literal characters of rendered segment content are emitted to the output buffer, and the only neutralization is a lookup in formats.EscapeSequences, which per shell contains only the shell's prompt-length markers (\ for bash, % for zsh, nothing for fish/pwsh/cmd/nu). Raw C0/C1 control bytes (ESC 0x1b, BEL 0x07, CSI, OSC) are written verbatim.

Oh My Posh's own styling is emitted through separate paths (writeEscapedAnsiString, writeColorise, builder.WriteString(formats.Hyperlink...)), so any control rune reaching write(s rune) originates from rendered data. trimAnsi is already applied to the console title (FormatTitle) but not to the prompt body.

Attacker-controlled sources (both verified)

  1. Current directory name (default config, Linux/macOS). Directory names may contain any byte except / and NUL, including 0x1b. The path segment renders the working directory in every theme.
  2. Git commit subject / author / upstream URL (cross-platform, including Windows). Git.Commit() runs git log -1 --pretty=format:...su:%s... and exposes .Commit.Subject, .Commit.Author.Name/.Email and .RawUpstreamURL; Git imposes no restriction on these, so they can carry raw escape sequences.

PoC

Git commit-subject vector (config: a single git segment with template {{ .Commit.Subject }}):

printf 'feat: \033]0;HACKED\007\033]52;c;ZWNobyBQV05FRA==\007 update' > msg.txt git commit --allow-empty -F msg.txt oh-my-posh print primary --config poc.omp.json --shell fish | xxd

Output (excerpt) shows the attacker's OSC 0 (set title) and OSC 52 (clipboard write) passed through unmodified, wrapped only in Oh My Posh's colors:

...255m feat: 1b5d 303b 4841 434b 4544 07 1b5d 3532 3b63 3b5a 574e ... 07 ... ESC ] 0 ; H A C K E D BEL ESC ] 5 2 ; c ; <base64> BEL

The directory-name vector reproduces identically via the path segment.

Impact

The terminal interprets the injected sequences on every render, enabling, per emulator: clipboard hijacking (OSC 52 write, so a command placed in the clipboard runs when the victim pastes), prompt/screen spoofing, window-title manipulation, and terminal denial of service. Delivery is remote (repo/archive/share); execution is local when the prompt renders after cd.

Suggested fix: neutralize C0/C1 control characters in untrusted segment data before it reaches the terminal, at minimum the path segment (folder names) and the git segment (Commit.Subject, Commit.Author.*, RawUpstreamURL). trimAnsi already exists and is applied to the title; extending equivalent handling to segment data closes the gap. Filtering control runes in write(s rune) would also work as defense in depth (Oh My Posh's own styling never flows through that function), optionally behind an opt-out for users who deliberately embed escapes in their own templates.

  • Published: Jul 24, 2026
  • Updated: Jul 25, 2026
  • GHSA: GHSA-fwjx-9p69-h25h
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 6.1
  • AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

CWEs:

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.