Critical severity · published May 19, 2026
CVE-2026-33642
Kitty has a Heap Buffer Over-Read/Write via Integer Overflow in compose_rectangles Bounds Check
9.8
CVSS
0.3%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KI
kitty · kovidgoyal
< 0.47.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33642
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33642
Patch
https://github.com/kovidgoyal/kitty/commit/e9661f0f3afb4e4dbffa509adfb3df3c9780ad34
Exploit
https://github.com/kovidgoyal/kitty/security/advisories/GHSA-qfgm-2c64-6x3x
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