UBUNTU-CVE-2026-53939

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Source
https://ubuntu.com/security/CVE-2026-53939
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53939.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-53939
Upstream
Published
2026-09-09T00:17:00Z
Modified
2026-09-16T14:01:43Z
Severity
  • 9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

OpenIDC/cjose is a C library implementing the Javascript Object Signing and Encryption (JOSE). In versions 0.6.1 through 0.6.2.5, when cjose encrypts a JWE using an AES-CBC-HMAC content-encryption algorithm (A128CBC-HS256, A192CBC-HS384, or A256CBC-HS512) together with any key-management algorithm that generates a fresh content-encryption key (CEK), the CEK is all zero bytes instead of being randomly generated. The resulting JWE is therefore encrypted and authenticated under a fixed, publicly known key, so anyone who obtains the JWE can recover the plaintext and forge or modify the content. This is fixed in version 0.6.2.6 by _cjose_jwe_set_cek_aes_cbc() generating the CEK from RAND_bytes. A regression test asserts that the encrypted_key differs across two encryptions for each AES-CBC-HMAC variant. Until upgrading, for data encrypted with cjose, three options are available. Use an AES-GCM enc (A128GCM / A192GCM / A256GCM) instead of an AES-CBC-HMAC enc, use alg=dir with a caller-supplied CEK, or avoid using cjose for JWE encryption with the affected algorithm pair. These are mitigations for new ciphertexts only; data already encrypted under the zero key remains compromised and should be re-encrypted (and any secrets it contained rotated).

References

Affected packages

Ubuntu:Pro:18.04:LTS / cjose

Package

Name
cjose
Purl
pkg:deb/ubuntu/cjose?arch=source&distro=esm-apps%2Fbionic

Affected ranges

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

Affected versions

0.*
0.4.1-3ubuntu1
0.5.1+dfsg1-1
0.5.1+dfsg1-2
0.5.1+dfsg1-2build1
0.6.0+dfsg1-1
0.6.0+dfsg1-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libcjose0",
            "binary_version":  "0.6.0+dfsg1-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53939.json"

Ubuntu:20.04:LTS / cjose

Package

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

Affected ranges

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

Affected versions

0.*
0.6.1+dfsg1-1
0.6.1+dfsg1-1ubuntu0.1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libcjose0",
            "binary_version":  "0.6.1+dfsg1-1ubuntu0.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53939.json"

Ubuntu:22.04:LTS / cjose

Package

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

Affected ranges

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

Affected versions

0.*
0.6.1+dfsg1-1
0.6.1+dfsg1-3
0.6.1+dfsg1-3ubuntu1
0.6.1+dfsg1-3ubuntu1.1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libcjose0",
            "binary_version":  "0.6.1+dfsg1-3ubuntu1.1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53939.json"

Ubuntu:24.04:LTS / cjose

Package

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

Affected ranges

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

Affected versions

0.*
0.6.2.2-1
0.6.2.2-1build1
0.6.2.2-1build2
0.6.2.2-1build3

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libcjose0",
            "binary_version":  "0.6.2.2-1build3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53939.json"

Ubuntu:26.04:LTS / cjose

Package

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

Affected ranges

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

Affected versions

0.*
0.6.2.3-1
0.6.2.4-1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libcjose0",
            "binary_version":  "0.6.2.4-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-53939.json"