UBUNTU-CVE-2026-44637

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Source
https://ubuntu.com/security/CVE-2026-44637
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44637.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-44637
Upstream
  • CVE-2026-44637
Published
2026-05-14T20:17:00Z
Modified
2026-05-20T22:03:08.765892827Z
Severity
  • 7.1 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a signed integer overflow in the SIXEL parser's image-buffer doubling loop can lead to an out-of-bounds heap write in sixeldecoderawimpl. context->posx grows by repeatcount on every sixel character with no upper bound check. Once posx approaches INTMAX, the expression "posx + repeat_count" used to size the image buffer overflows signed int. Depending on how the overflow wraps, the resize check that should reject oversized buffers can be bypassed, after which a subsequent write computes a large attacker-influenced offset into image->data and writes past the allocation. Reachable from any caller that decodes attacker-supplied SIXEL data, including img2sixel. This vulnerability is fixed in 1.8.7-r2.

References

Affected packages

Ubuntu:16.04:LTS
libsixel

Package

Name
libsixel
Purl
pkg:deb/ubuntu/libsixel?arch=source&distro=xenial

Affected ranges

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

Affected versions

1.*
1.4.2-1
1.5.2-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libsixel-bin",
            "binary_version": "1.5.2-2"
        },
        {
            "binary_name": "libsixel1",
            "binary_version": "1.5.2-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44637.json"
Ubuntu:18.04:LTS
libsixel

Package

Name
libsixel
Purl
pkg:deb/ubuntu/libsixel?arch=source&distro=bionic

Affected ranges

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

Affected versions

1.*
1.5.2-2
1.7.3-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libsixel-bin",
            "binary_version": "1.7.3-1"
        },
        {
            "binary_name": "libsixel-examples",
            "binary_version": "1.7.3-1"
        },
        {
            "binary_name": "libsixel1",
            "binary_version": "1.7.3-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44637.json"
Ubuntu:20.04:LTS
libsixel

Package

Name
libsixel
Purl
pkg:deb/ubuntu/libsixel?arch=source&distro=focal

Affected ranges

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

Affected versions

1.*
1.8.2-1
1.8.2-2.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libsixel-bin",
            "binary_version": "1.8.2-2.1"
        },
        {
            "binary_name": "libsixel-examples",
            "binary_version": "1.8.2-2.1"
        },
        {
            "binary_name": "libsixel1",
            "binary_version": "1.8.2-2.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44637.json"
Ubuntu:22.04:LTS
libsixel

Package

Name
libsixel
Purl
pkg:deb/ubuntu/libsixel?arch=source&distro=jammy

Affected ranges

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

Affected versions

1.*
1.8.6-2
1.10.3-2
1.10.3-3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libsixel-bin",
            "binary_version": "1.10.3-3"
        },
        {
            "binary_name": "libsixel-examples",
            "binary_version": "1.10.3-3"
        },
        {
            "binary_name": "libsixel1",
            "binary_version": "1.10.3-3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44637.json"
Ubuntu:24.04:LTS
libsixel

Package

Name
libsixel
Purl
pkg:deb/ubuntu/libsixel?arch=source&distro=noble

Affected ranges

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

Affected versions

1.*
1.10.3-3
1.10.3-3build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libsixel-bin",
            "binary_version": "1.10.3-3build1"
        },
        {
            "binary_name": "libsixel-examples",
            "binary_version": "1.10.3-3build1"
        },
        {
            "binary_name": "libsixel1",
            "binary_version": "1.10.3-3build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44637.json"
Ubuntu:25.10
libsixel

Package

Name
libsixel
Purl
pkg:deb/ubuntu/libsixel?arch=source&distro=questing

Affected ranges

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

Affected versions

1.*
1.10.5-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libsixel-bin",
            "binary_version": "1.10.5-1"
        },
        {
            "binary_name": "libsixel-examples",
            "binary_version": "1.10.5-1"
        },
        {
            "binary_name": "libsixel1",
            "binary_version": "1.10.5-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44637.json"
Ubuntu:26.04:LTS
libsixel

Package

Name
libsixel
Purl
pkg:deb/ubuntu/libsixel?arch=source&distro=resolute

Affected ranges

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

Affected versions

1.*
1.10.5-1
1.10.5-1build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "libsixel-bin",
            "binary_version": "1.10.5-1build1"
        },
        {
            "binary_name": "libsixel-examples",
            "binary_version": "1.10.5-1build1"
        },
        {
            "binary_name": "libsixel1",
            "binary_version": "1.10.5-1build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44637.json"