Kitty terminal CVE-2026-33633

Exploitation requires that the attacker can write bytes to the Kitty process's stdin or controlling TTY, the target must be running Kitty 0.46.2 or earlier, and Kitty's graphics protocol must be enabled (it is on by default). The attacker must deliver a single APC graphics protocol command with the PNG format declaration f=100 carrying a payload larger than twice load_image_data()'s initial buffer capacity. Limiting factors per CVSS AV:N/AC:H/UI:R: high attack complexity and required user interaction - the victim has to perform an action that pipes attacker-controlled output into Kitty (viewing a malicious file, SSHing to a compromised host, tailing a poisoned log, or running a hostile local program); no authentication to Kitty itself is required (PR:N) and scope is unchanged.

The CVSS 3.1 vector AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H yields 7.5 (High) and signals an unauthenticated network-reachable attack but with high complexity and required user interaction - realistic because exploitation requires getting attacker-controlled bytes piped into a victim's terminal stdin (e.g., catting a malicious file, viewing a crafted log over SSH, or a hostile process on the same host). EPSS and CISA KEV status were not supplied in the input, and no public exploit identified at time of analysis, so this is not currently a mass-exploitation candidate; the realistic risk profile is targeted abuse against developers, sysadmins, and CTF/forensics workflows where untrusted output is commonly displayed. The vendor confirms DoS is reliably triggerable and notes RCE is potentially reachable given the attacker-controlled length and content, but no public weaponization demonstrating code execution has been provided in the references - RCE remains an inferred upper bound, not a confirmed capability.

An attacker who can place bytes into a user's terminal stdin - for instance via a malicious file the user runs cat on, a compromised remote host the user SSHes into, a poisoned log file tailed during incident response, or a hostile local process sharing the TTY - emits a single APC graphics command with f=100 and a PNG payload more than twice the initial buffer capacity. Kitty's load_image_data() overruns its heap allocation with attacker-controlled bytes, immediately crashing the terminal (denial of service) and, per the vendor advisory, potentially allowing escalation to code execution in the terminal process. No public proof-of-concept has been identified at time of analysis.