DEBIAN-CVE-2026-80431

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Source
https://security-tracker.debian.org/tracker/CVE-2026-80431
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-80431.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-80431
Upstream
Published
2026-09-25T14:17:19Z
Modified
2026-09-26T10:00:07Z
Severity
  • 6.8 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X CVSS Calculator
Summary
[none]
Details

Out-of-bounds Write in the natural width branch of the text sizing protocol in kitty from 0.40.0 before 0.49.0 allows a program writing to the terminal to write past the end of a fixed-size buffer, because screen_handle_multicell_command() in kitty/screen.c appends each codepoint of a grapheme cluster with lc.chars[lc.count++] = ch without any capacity check, while lc is declared by the RAII_ListOfChars macro as a four-element char_type array in the function's stack frame, so an OSC 66 escape code whose payload carries a grapheme cluster longer than four codepoints writes beyond that buffer, one 32-bit value per additional codepoint, in the order the codepoints appear. Where the cluster is preceded in the same payload by a sequence that causes an intermediate flush, the buffer is first migrated to the heap by ensure_space_for_chars() and the write occurs past the heap allocation instead. This results in termination of the kitty process and therefore of all its windows, tabs and child processes.

References

Affected packages

Debian:12 / kitty

Package

Name
kitty
Purl
pkg:deb/debian/kitty?arch=source&distro=bookworm

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.26.5-5
0.30.1-1
0.31.0-1
0.31.0-2
0.31.0-3
0.31.0-4
0.32.0-1
0.32.1-1
0.32.2-1
0.33.0-2
0.33.1-1
0.34.1-1
0.35.1-1
0.35.2-1
0.36.1-1
0.36.4-1
0.36.4-2
0.36.4-3
0.37.0-1
0.38.1-1
0.39.0-1
0.39.1-1
0.40.0-1
0.41.1-1
0.41.1-2
0.42.1-1
0.42.2-1
0.43.1-1
0.44.0-1
0.45.0-1
0.45.0-2
0.46.1-1
0.46.2-1
0.47.0-1
0.47.0-2
0.47.0-3
0.47.3-1
0.47.4-1
0.48.2-1
0.48.2-1.1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-80431.json"

Debian:13 / kitty

Package

Name
kitty
Purl
pkg:deb/debian/kitty?arch=source&distro=trixie

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.41.1-2
0.41.1-2+deb13u1
0.41.1-2+deb13u2
0.42.1-1
0.42.2-1
0.43.1-1
0.44.0-1
0.45.0-1
0.45.0-2
0.46.1-1
0.46.2-1
0.47.0-1
0.47.0-2
0.47.0-3
0.47.3-1
0.47.4-1
0.48.2-1
0.48.2-1.1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-80431.json"

Debian:14 / kitty

Package

Name
kitty
Purl
pkg:deb/debian/kitty?arch=source&distro=forky

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

0.*
0.41.1-2
0.42.1-1
0.42.2-1
0.43.1-1
0.44.0-1
0.45.0-1
0.45.0-2
0.46.1-1
0.46.2-1
0.47.0-1
0.47.0-2
0.47.0-3
0.47.3-1
0.47.4-1
0.48.2-1
0.48.2-1.1

Ecosystem specific 

{
    "urgency":  "not yet assigned"
}

Database specific

source 
"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-80431.json"