DEBIAN-CVE-2026-44636
libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, signed integer overflow in sixel_encode_highcolor's allocation size calculation can lead to a heap buffer overflow. The public sixel_encode entry point validates only that width and height are greater than zero, with no upper bound. width and height are multiplied as plain int when computing the allocation size for paletted_pixels and normalized_pixels. Any caller that asks libsixel to encode a pixel buffer with width times height greater than INT_MAX (about 2.15 billion) will hit a wrapped allocation size; under the right wrap, the malloc succeeds with a buffer much smaller than the encoder expects, and the encoder writes past the end of the heap allocation. This vulnerability is fixed in 1.8.7-r2.
DEBIAN-CVE-2026-44636
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-44636
libsixel
Source reference: /affected/0/package/name
- Affected versions
- 1.10.3-3
Source reference:
/affected/0/versions1.10.5-1Source reference:
/affected/0/versions1:1.8.7-1Source reference:
/affected/0/versions1:1.8.7-2Source reference:
/affected/0/versions1:1.8.7-3Source reference:
/affected/0/versions1:1.8.7-4Source reference:
/affected/0/versions1:1.8.7-5Source reference:
/affected/0/versions1:1.8.7-6Source reference:
/affected/0/versions1:1.8.7-r2-1Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
libsixel
Source reference: /affected/1/package/name
- Affected versions
- 1.10.5-1
Source reference:
/affected/1/versions1:1.8.7-1Source reference:
/affected/1/versions1:1.8.7-2Source reference:
/affected/1/versions1:1.8.7-3Source reference:
/affected/1/versions1:1.8.7-4Source reference:
/affected/1/versions1:1.8.7-5Source reference:
/affected/1/versions1:1.8.7-6Source reference:
/affected/1/versions1:1.8.7-r2-1Source reference:
/affected/1/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
libsixel
Source reference: /affected/2/package/name
- Affected versions
- 1.10.5-1
Source reference:
/affected/2/versions1:1.8.7-1Source reference:
/affected/2/versions1:1.8.7-2Source reference:
/affected/2/versions1:1.8.7-3Source reference:
/affected/2/versions1:1.8.7-4Source reference:
/affected/2/versions1:1.8.7-5Source reference:
/affected/2/versions1:1.8.7-6Source reference:
/affected/2/versions - Fixed versions
- 1:1.8.7-r2-1
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libsixel",
"purl": "pkg:deb/debian/libsixel?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.10.3-3",
"1.10.5-1",
"1:1.8.7-1",
"1:1.8.7-2",
"1:1.8.7-3",
"1:1.8.7-4",
"1:1.8.7-5",
"1:1.8.7-6",
"1:1.8.7-r2-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44636.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libsixel",
"purl": "pkg:deb/debian/libsixel?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.10.5-1",
"1:1.8.7-1",
"1:1.8.7-2",
"1:1.8.7-3",
"1:1.8.7-4",
"1:1.8.7-5",
"1:1.8.7-6",
"1:1.8.7-r2-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44636.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:1.8.7-r2-1"
}
]
}
],
"package": {
"name": "libsixel",
"purl": "pkg:deb/debian/libsixel?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.10.5-1",
"1:1.8.7-1",
"1:1.8.7-2",
"1:1.8.7-3",
"1:1.8.7-4",
"1:1.8.7-5",
"1:1.8.7-6"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44636.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #57072 · Revision 1
- Added to Heist Feed
- Publisher date