UBUNTU-CVE-2026-34872

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Source
https://ubuntu.com/security/CVE-2026-34872
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34872.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-34872
Upstream
  • CVE-2026-34872
Published
2026-04-01T20:16:00Z
Modified
2026-05-20T16:25:34.985186677Z
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

An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).

References

Affected packages

Ubuntu:16.04:LTS
mbedtls

Package

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

Affected ranges

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

Affected versions

2.*
2.1.2-1
2.2.0-1
2.2.1-1
2.2.1-2
2.2.1-2ubuntu0.1
2.2.1-2ubuntu0.2
2.2.1-2ubuntu0.3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.2.1-2ubuntu0.3",
            "binary_name": "libmbedcrypto0"
        },
        {
            "binary_version": "2.2.1-2ubuntu0.3",
            "binary_name": "libmbedtls10"
        },
        {
            "binary_version": "2.2.1-2ubuntu0.3",
            "binary_name": "libmbedx509-0"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34872.json"
Ubuntu:25.10
mbedtls

Package

Name
mbedtls
Purl
pkg:deb/ubuntu/mbedtls?arch=source&distro=questing

Affected ranges

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

Affected versions

3.*
3.6.2-3ubuntu1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.6.2-3ubuntu1",
            "binary_name": "libmbedcrypto16"
        },
        {
            "binary_version": "3.6.2-3ubuntu1",
            "binary_name": "libmbedtls21"
        },
        {
            "binary_version": "3.6.2-3ubuntu1",
            "binary_name": "libmbedx509-7"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34872.json"
Ubuntu:26.04:LTS
mbedtls

Package

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

Affected ranges

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

Affected versions

3.*
3.6.2-3ubuntu1
3.6.5-0.1ubuntu1
3.6.5-0.1ubuntu2

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "3.6.5-0.1ubuntu2",
            "binary_name": "libmbedcrypto16"
        },
        {
            "binary_version": "3.6.5-0.1ubuntu2",
            "binary_name": "libmbedtls21"
        },
        {
            "binary_version": "3.6.5-0.1ubuntu2",
            "binary_name": "libmbedx509-7"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34872.json"
Ubuntu:Pro:18.04:LTS
mbedtls

Package

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

Affected ranges

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

Affected versions

2.*
2.5.1-1ubuntu1
2.6.0-1
2.7.0-2
2.8.0-1
2.8.0-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.8.0-1ubuntu0.1~esm1",
            "binary_name": "libmbedcrypto1"
        },
        {
            "binary_version": "2.8.0-1ubuntu0.1~esm1",
            "binary_name": "libmbedtls10"
        },
        {
            "binary_version": "2.8.0-1ubuntu0.1~esm1",
            "binary_name": "libmbedx509-0"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34872.json"
Ubuntu:Pro:20.04:LTS
mbedtls

Package

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

Affected ranges

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

Affected versions

2.*
2.16.2-1
2.16.3-1
2.16.4-1ubuntu2
2.16.4-1ubuntu2+esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.16.4-1ubuntu2+esm1",
            "binary_name": "libmbedcrypto3"
        },
        {
            "binary_version": "2.16.4-1ubuntu2+esm1",
            "binary_name": "libmbedtls12"
        },
        {
            "binary_version": "2.16.4-1ubuntu2+esm1",
            "binary_name": "libmbedx509-0"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34872.json"
Ubuntu:Pro:22.04:LTS
mbedtls

Package

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

Affected ranges

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

Affected versions

2.*
2.16.9-0.1ubuntu1
2.16.11-0.1ubuntu1
2.16.11-0.3
2.28.0-1
2.28.0-1build1
2.28.0-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.28.0-1ubuntu0.1~esm1",
            "binary_name": "libmbedcrypto7"
        },
        {
            "binary_version": "2.28.0-1ubuntu0.1~esm1",
            "binary_name": "libmbedtls14"
        },
        {
            "binary_version": "2.28.0-1ubuntu0.1~esm1",
            "binary_name": "libmbedx509-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34872.json"
Ubuntu:Pro:24.04:LTS
mbedtls

Package

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

Affected ranges

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

Affected versions

2.*
2.28.3-1
2.28.6-1ubuntu1
2.28.7-1ubuntu1
2.28.7-1.1ubuntu1
2.28.8-1
2.28.8-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_version": "2.28.8-1ubuntu0.1~esm1",
            "binary_name": "libmbedcrypto7t64"
        },
        {
            "binary_version": "2.28.8-1ubuntu0.1~esm1",
            "binary_name": "libmbedtls14t64"
        },
        {
            "binary_version": "2.28.8-1ubuntu0.1~esm1",
            "binary_name": "libmbedx509-1t64"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-34872.json"