Out-of-bounds Read in Kovidgoyal Kitty
CVE-2026-33642
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.
Vulnerability class: Buffer Overflow
EPSS: 0.003 (21.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:H.
Affected products
- Kovidgoyal Kitty — versions < 0.47.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Mitigation, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-33642?
- CVE-2026-33642 is a critical-severity vulnerability in Kovidgoyal Kitty, classified under Out-of-bounds Read. CVSS score: 9.9/10. Published 2026-05-19.
- How severe is CVE-2026-33642?
- Critical severity. CVSS v3 base score is 9.9 out of 10.