CVE-2026-54057: Kitty vulnerable to command injection via unsanitized OSC 21 query reply

Synopsis

Command injection via unsanitized OSC 21 query reply affects Kitty, a GPU-accelerated cross-platform terminal emulator. The attack runs locally and requires no authenticated account, but does require a victim to interact with attacker-controlled terminal output, typically by opening a crafted file or visiting a malicious page that emits escape sequences. Successful exploitation gives the attacker full read, write, and availability control over the victim's active shell session. HarborGuard tracks this advisory and will make a patched-image rebuild available the moment an upstream fix is published.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityNot required

  The attacker needs an existing shell or process on the host; no network exposure to the vulnerable service is required.

• AuthenticationNot required

  No account or credential of any privilege level is needed to deliver the malicious OSC 21 escape sequence.

• Victim interactionRequired

  The victim must interact with attacker-controlled terminal output, for example by opening a crafted file or navigating to content that emits the malicious escape sequence in the terminal.

• Attack complexityDetail

  Attack-target conditions must align (AT:P), meaning the attacker depends on specific environmental factors such as the victim having an active Kitty session and a vulnerable version present, though no memory-layout or race-condition exploitation is required.

Blast Radius

• Reads files, environment variables, shell history, and session tokens accessible to the victim user's shell process.
• Executes arbitrary shell commands under the victim user's identity, modifying or deleting files and persisted data the user can reach.
• Crashes or hijacks the active terminal session, disrupting the victim's running processes and workflows.