UBUNTU-CVE-2026-65632

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Source
https://ubuntu.com/security/CVE-2026-65632
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65632.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-65632
Upstream
Published
2026-10-26T20:17:00Z
Modified
2026-10-28T20:17:48Z
Severity
  • 5.1 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CVSS Calculator
  • 5.1 (Medium) CVSS_V4 - CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

The jose library accepts ECDSA (ES256, ES256K, ES384, and ES512) JWS signatures of a non-canonical length. When verifying an ECDSA signature, jose_jwk_kty_ec:verify/4 in src/jwk/jose_jwk_kty_ec.erl splits the raw signature in half by its actual byte length (split_binary(Signature, byte_size(Signature) div 2)) instead of enforcing the fixed length required by RFC 7518 ยง3.4, and then decodes each half with crypto:bytes_to_integer/1, which ignores leading zero bytes. As a result, an attacker who holds one valid token can prepend leading zero bytes to each of the R and S halves to produce longer signatures that still split evenly and decode to the same (r, s) pair, so many distinct signature byte strings all verify against the same key (signature malleability). This does not allow forging new payloads or impersonating a signer, because the underlying (r, s) values are unchanged. It does defeat any security control that assumes a valid token or its signature is unique, such as token-revocation-by-hash, replay or idempotency caches, and deduplication logic. This issue affects jose: from 1.0.0 before 1.11.13.

References

Affected packages

Ubuntu:18.04:LTS
jose

Package

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

Affected ranges

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

Affected versions

Other
10-2
10-2build1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "jose",
            "binary_version":  "10-2build1"
        },
        {
            "binary_name":  "libjose0",
            "binary_version":  "10-2build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65632.json"
Ubuntu:20.04:LTS
jose

Package

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

Affected ranges

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

Affected versions

Other
10-2build2

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "jose",
            "binary_version":  "10-2build2"
        },
        {
            "binary_name":  "libjose0",
            "binary_version":  "10-2build2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65632.json"
Ubuntu:22.04:LTS
jose

Package

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

Affected ranges

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

Affected versions

Other
10-3
11-2

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "jose",
            "binary_version":  "11-2"
        },
        {
            "binary_name":  "libjose0",
            "binary_version":  "11-2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65632.json"
Ubuntu:24.04:LTS
jose

Package

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

Affected ranges

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

Affected versions

Other
11-2
11-3
11-3build1
11-3build2
13-1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "jose",
            "binary_version":  "13-1"
        },
        {
            "binary_name":  "libjose0",
            "binary_version":  "13-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65632.json"
Ubuntu:26.04:LTS
jose

Package

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

Affected ranges

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

Affected versions

Other
14-2build1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "jose",
            "binary_version":  "14-2build1"
        },
        {
            "binary_name":  "libjose0",
            "binary_version":  "14-2build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65632.json"
Ubuntu:26.10
jose

Package

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

Affected ranges

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

Affected versions

Other
14-2build1
14-2build2

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "jose",
            "binary_version":  "14-2build2"
        },
        {
            "binary_name":  "libjose0",
            "binary_version":  "14-2build2"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-65632.json"