Vulnerability Description
Kitty is a cross-platform GPU based terminal. In versions 0.46.2 and below, the handle_compose_command() function in kitty/graphics.c performs bounds validation on composition offsets using unsigned 32-bit arithmetic that is subject to integer wrapping, potentially leading to Heap Buffer Over-Read/Write. An attacker who can write escape sequences to a kitty terminal (e.g., via a malicious file, SSH login banner, or piped content) can supply crafted x_offset/y_offset values that pass the bounds check after wrapping but cause massive out-of-bounds heap memory access in compose_rectangles(). No user interaction is required. No non-default configuration is required. The attacker only needs the ability to produce output in a kitty terminal window. This issue has been fixed in version 0.47.0.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/kovidgoyal/kitty/commit/e9661f0f3afb4e4dbffa509adfb3df3c9780a
- https://github.com/kovidgoyal/kitty/security/advisories/GHSA-qfgm-2c64-6x3x
- https://github.com/kovidgoyal/kitty/security/advisories/GHSA-qfgm-2c64-6x3x
FAQ
What is CVE-2026-33642?
CVE-2026-33642 is a vulnerability with a CVSS score of 9.9 (CRITICAL). Kitty is a cross-platform GPU based terminal. In versions 0.46.2 and below, the handle_compose_command() function in kitty/graphics.c performs bounds validation on composition offsets using unsigned 3...
How severe is CVE-2026-33642?
CVE-2026-33642 has been rated CRITICAL with a CVSS base score of 9.9/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-33642?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.