UBUNTU-CVE-2026-123785

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Source
https://ubuntu.com/security/CVE-2026-123785
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123785.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-123785
Upstream
Published
2026-11-09T00:00:00Z
Modified
2026-11-10T02:50:22Z
Severity
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H CVSS Calculator
  • 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 CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

Fluxbox through 1.3.7 contains an infinite loop vulnerability in Menu::updateMenu() in src/FbTk/Menu.cc that allows attackers to hang the window manager via crafted style geometry values. Attackers can supply a style with an oversized unbounded menu.titleHeight so the column loop never terminates, causing sustained CPU use and denial of service at startup.

References

Affected packages

Ubuntu:16.04:LTS
fluxbox

Package

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

Affected ranges

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

Affected versions

1.*
1.3.5-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "fluxbox",
            "binary_version": "1.3.5-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123785.json"
Ubuntu:18.04:LTS
fluxbox

Package

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

Affected ranges

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

Affected versions

1.*
1.3.5-2
1.3.5-2build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "fluxbox",
            "binary_version": "1.3.5-2build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123785.json"
Ubuntu:20.04:LTS
fluxbox

Package

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

Affected ranges

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

Affected versions

1.*
1.3.5-2build1
1.3.5-2build2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "fluxbox",
            "binary_version": "1.3.5-2build2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123785.json"
Ubuntu:22.04:LTS
fluxbox

Package

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

Affected ranges

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

Affected versions

1.*
1.3.5-2build2
1.3.5-2.1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "fluxbox",
            "binary_version": "1.3.5-2.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123785.json"
Ubuntu:24.04:LTS
fluxbox

Package

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

Affected ranges

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

Affected versions

1.*
1.3.7-1
1.3.7-1build1
1.3.7-1build2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "fluxbox",
            "binary_version": "1.3.7-1build2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123785.json"
Ubuntu:26.04:LTS
fluxbox

Package

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

Affected ranges

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

Affected versions

1.*
1.3.7-1build2
1.3.7-1build3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "fluxbox",
            "binary_version": "1.3.7-1build3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123785.json"
Ubuntu:26.10
fluxbox

Package

Name
fluxbox
Purl
pkg:deb/ubuntu/fluxbox?arch=source&distro=stonking

Affected ranges

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

Affected versions

1.*
1.3.7-1build3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "fluxbox",
            "binary_version": "1.3.7-1build3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-123785.json"