UBUNTU-CVE-2026-39373

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Source
https://ubuntu.com/security/CVE-2026-39373
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json
JSON Data
https://api.test.osv.dev/v1/vulns/UBUNTU-CVE-2026-39373
Upstream
Published
2026-04-07T20:16:00Z
Modified
2026-04-27T20:14:19.745278Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

JWCrypto implements JWK, JWS, and JWE specifications using python-cryptography. Prior to 1.5.7, an unauthenticated attacker can exhaust server memory by sending crafted JWE tokens with ZIP compression. The existing patch for CVE-2024-28102 limits input token size to 250KB but does not validate the decompressed output size. An unauthenticated attacker can cause memory exhaustion on memory-constrained systems. A token under the 250KB input limit can decompress to approximately 100MB. This vulnerability is fixed in 1.5.7.

References

Affected packages

Ubuntu:16.04:LTS
python-jwcrypto

Package

Name
python-jwcrypto
Purl
pkg:deb/ubuntu/python-jwcrypto@0.2.1-1?arch=source&distro=xenial

Affected ranges

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

Affected versions

0.*
0.2.1-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python-jwcrypto",
            "binary_version": "0.2.1-1"
        },
        {
            "binary_name": "python3-jwcrypto",
            "binary_version": "0.2.1-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"
Ubuntu:18.04:LTS
python-jwcrypto

Package

Name
python-jwcrypto
Purl
pkg:deb/ubuntu/python-jwcrypto@0.4.2-1?arch=source&distro=bionic

Affected ranges

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

Affected versions

0.*
0.3.2-1
0.4.2-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python-jwcrypto",
            "binary_version": "0.4.2-1"
        },
        {
            "binary_name": "python3-jwcrypto",
            "binary_version": "0.4.2-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"
Ubuntu:20.04:LTS
python-jwcrypto

Package

Name
python-jwcrypto
Purl
pkg:deb/ubuntu/python-jwcrypto@0.6.0-2?arch=source&distro=focal

Affected ranges

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

Affected versions

0.*
0.6.0-1
0.6.0-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-jwcrypto",
            "binary_version": "0.6.0-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"
Ubuntu:22.04:LTS
python-jwcrypto

Package

Name
python-jwcrypto
Purl
pkg:deb/ubuntu/python-jwcrypto@1.0.0-2?arch=source&distro=jammy

Affected ranges

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

Affected versions

0.*
0.8.0-1
1.*
1.0.0-2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-jwcrypto",
            "binary_version": "1.0.0-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"
Ubuntu:24.04:LTS
python-jwcrypto

Package

Name
python-jwcrypto
Purl
pkg:deb/ubuntu/python-jwcrypto@1.5.4-1?arch=source&distro=noble

Affected ranges

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

Affected versions

1.*
1.1.0-1
1.5.4-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-jwcrypto",
            "binary_version": "1.5.4-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"
Ubuntu:25.10
python-jwcrypto

Package

Name
python-jwcrypto
Purl
pkg:deb/ubuntu/python-jwcrypto@1.5.6-1?arch=source&distro=questing

Affected ranges

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

Affected versions

1.*
1.5.6-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-jwcrypto",
            "binary_version": "1.5.6-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"
Ubuntu:26.04
python-jwcrypto

Package

Name
python-jwcrypto
Purl
pkg:deb/ubuntu/python-jwcrypto@1.5.6-1?arch=source&distro=resolute

Affected ranges

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

Affected versions

1.*
1.5.6-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-jwcrypto",
            "binary_version": "1.5.6-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39373.json"