UBUNTU-CVE-2026-33228

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Source
https://ubuntu.com/security/CVE-2026-33228
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33228.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-33228
Upstream
Published
2026-03-20T23:16:00Z
Modified
2026-05-20T16:25:27.268509630Z
Severity
  • 8.9 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P CVSS Calculator
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the internal input buffer is a JavaScript Array, accessing it with the key "proto" returns Array.prototype via the inherited getter. This object is then treated as a legitimate parsed value and assigned as a property of the output object, effectively leaking a live reference to Array.prototype to the consumer. Any code that subsequently writes to that property will pollute the global prototype. This issue has been patched in version 3.4.2.

References

Affected packages

Ubuntu:20.04:LTS / node-flatted

Package

Name
node-flatted
Purl
pkg:deb/ubuntu/node-flatted?arch=source&distro=focal

Affected ranges

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

Affected versions

2.*
2.0.1~dfsg-3
2.0.1~dfsg-4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.0.1~dfsg-4",
            "binary_name": "libjs-flatted"
        },
        {
            "binary_version": "2.0.1~dfsg-4",
            "binary_name": "node-flatted"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33228.json"

Ubuntu:22.04:LTS / node-flatted

Package

Name
node-flatted
Purl
pkg:deb/ubuntu/node-flatted?arch=source&distro=jammy

Affected ranges

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

Affected versions

2.*
2.0.2~dfsg-1
2.0.2~dfsg-4
3.*
3.2.2~ds-2
3.2.2~ds-3
3.2.4~ds-1
3.2.5~ds-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.2.5~ds-1",
            "binary_name": "libjs-flatted"
        },
        {
            "binary_version": "3.2.5~ds-1",
            "binary_name": "node-flatted"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33228.json"

Ubuntu:24.04:LTS / node-flatted

Package

Name
node-flatted
Purl
pkg:deb/ubuntu/node-flatted?arch=source&distro=noble

Affected ranges

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

Affected versions

3.*
3.2.7~ds-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.2.7~ds-1",
            "binary_name": "libjs-flatted"
        },
        {
            "binary_version": "3.2.7~ds-1",
            "binary_name": "node-flatted"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33228.json"

Ubuntu:25.10 / node-flatted

Package

Name
node-flatted
Purl
pkg:deb/ubuntu/node-flatted?arch=source&distro=questing

Affected ranges

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

Affected versions

3.*
3.2.7~ds-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.2.7~ds-1",
            "binary_name": "libjs-flatted"
        },
        {
            "binary_version": "3.2.7~ds-1",
            "binary_name": "node-flatted"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33228.json"

Ubuntu:26.04:LTS / node-flatted

Package

Name
node-flatted
Purl
pkg:deb/ubuntu/node-flatted?arch=source&distro=resolute

Affected ranges

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

Affected versions

3.*
3.2.7~ds-1
3.4.2~ds-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.4.2~ds-1",
            "binary_name": "libjs-flatted"
        },
        {
            "binary_version": "3.4.2~ds-1",
            "binary_name": "node-flatted"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33228.json"