UBUNTU-CVE-2026-71889

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Source
https://ubuntu.com/security/CVE-2026-71889
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71889.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-71889
Upstream
Published
2026-10-05T00:00:00Z
Modified
2026-10-05T13:04:12Z
Severity
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

In Bouncy Castle for Java before 1.86, neither copy of PKIXCertPathReviewer - org.bouncycastle.pkix.jcajce.PKIXCertPathReviewer nor the legacy org.bouncycastle.x509.PKIXCertPathReviewer - applied X.509 name constraints to the end-entity certificate. checkNameConstraints walked the path with a loop bound of index greater than zero, which is the bound the CA-only steps require, but index zero is the target certificate under the standard CertPath ordering, so the permitted and excluded subtree checks of RFC 5280 sec. 6.1.3 (b) and (c) never ran against the leaf's subject DN or its subjectAltName. A chain whose leaf violated a NameConstraints extension imposed by its own issuing CA therefore reported isValidCertPath() true with an empty error list, while CertPathValidator.getInstance("PKIX", "BC"), which shares no code with the reviewer, rejected the identical chain against the identical trust anchor. An application using the reviewer to make the trust decision rather than for diagnostics alongside a real validation accepted a certificate the constrained CA was never authorised to issue. Both copies now check every certificate in the path including the target, waive the sec. 4.2.1.10 self-issued exemption for the final certificate as sec. 6.1.3 requires, and skip the sec. 6.1.4 (g) constraint-accumulation step for the target. This issue also affects Bouncy Castle for Java LTS before 2.73.13, which carries only the org.bouncycastle.pkix.jcajce copy of the reviewer. It also affects Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).

References

Affected packages

Ubuntu:26.04:LTS
bouncycastle

Package

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

Affected ranges

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

Affected versions

1.*
1.80-3

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libbcjmail-java",
            "binary_version":  "1.80-3"
        },
        {
            "binary_name":  "libbcmail-java",
            "binary_version":  "1.80-3"
        },
        {
            "binary_name":  "libbcpg-java",
            "binary_version":  "1.80-3"
        },
        {
            "binary_name":  "libbcpkix-java",
            "binary_version":  "1.80-3"
        },
        {
            "binary_name":  "libbcprov-java",
            "binary_version":  "1.80-3"
        },
        {
            "binary_name":  "libbctls-java",
            "binary_version":  "1.80-3"
        },
        {
            "binary_name":  "libbcutil-java",
            "binary_version":  "1.80-3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71889.json"
Ubuntu:Pro:16.04:LTS
bouncycastle

Package

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

Affected ranges

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

Affected versions

1.*
1.49+dfsg-3ubuntu1
1.51-4ubuntu1
1.51-4ubuntu1+esm1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libbcmail-java",
            "binary_version":  "1.51-4ubuntu1+esm1"
        },
        {
            "binary_name":  "libbcpg-java",
            "binary_version":  "1.51-4ubuntu1+esm1"
        },
        {
            "binary_name":  "libbcpkix-java",
            "binary_version":  "1.51-4ubuntu1+esm1"
        },
        {
            "binary_name":  "libbcprov-java",
            "binary_version":  "1.51-4ubuntu1+esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71889.json"
Ubuntu:Pro:18.04:LTS
bouncycastle

Package

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

Affected ranges

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

Affected versions

1.*
1.57-1
1.58-1
1.59-1
1.59-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libbcmail-java",
            "binary_version":  "1.59-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcpg-java",
            "binary_version":  "1.59-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcpkix-java",
            "binary_version":  "1.59-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcprov-java",
            "binary_version":  "1.59-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71889.json"
Ubuntu:Pro:20.04:LTS
bouncycastle

Package

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

Affected ranges

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

Affected versions

1.*
1.61-1
1.61-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libbcmail-java",
            "binary_version":  "1.61-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcpg-java",
            "binary_version":  "1.61-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcpkix-java",
            "binary_version":  "1.61-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcprov-java",
            "binary_version":  "1.61-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71889.json"
Ubuntu:Pro:22.04:LTS
bouncycastle

Package

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

Affected ranges

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

Affected versions

1.*
1.68-2
1.68-4
1.68-5
1.68-5ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libbcmail-java",
            "binary_version":  "1.68-5ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcpg-java",
            "binary_version":  "1.68-5ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcpkix-java",
            "binary_version":  "1.68-5ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcprov-java",
            "binary_version":  "1.68-5ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbctls-java",
            "binary_version":  "1.68-5ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71889.json"
Ubuntu:Pro:24.04:LTS
bouncycastle

Package

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

Affected ranges

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

Affected versions

1.*
1.72-2
1.77-1
1.77-1ubuntu0.1~esm1

Ecosystem specific 

{
    "binaries":  [
        {
            "binary_name":  "libbcjmail-java",
            "binary_version":  "1.77-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcmail-java",
            "binary_version":  "1.77-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcpg-java",
            "binary_version":  "1.77-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcpkix-java",
            "binary_version":  "1.77-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcprov-java",
            "binary_version":  "1.77-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbctls-java",
            "binary_version":  "1.77-1ubuntu0.1~esm1"
        },
        {
            "binary_name":  "libbcutil-java",
            "binary_version":  "1.77-1ubuntu0.1~esm1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71889.json"