UBUNTU-CVE-2026-54906

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Source
https://ubuntu.com/security/CVE-2026-54906
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54906.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-54906
Upstream
Published
2026-06-24T17:17:00Z
Modified
2026-06-29T13:56:55.029975909Z
Severity
  • 2.1 (Low) CVSS_V4 - CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N CVSS Calculator
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::ReadWriteLock#releasewritelock does not verify that the calling thread acquired the write lock. Any thread with access to the lock object can release an active write lock held by another thread. A second writer can then enter its critical section while the first writer is still running. Concurrent::ReadWriteLock#releasereadlock also decrements the shared counter even when no read lock is held. Calling it on a fresh lock changes the counter from 0 to -1, after which normal read acquisition raises Concurrent::ResourceLimitError. This is a synchronization correctness issue in the public Concurrent::ReadWriteLock API. This vulnerability is fixed in 1.3.7.

References

Affected packages

Ubuntu:16.04:LTS
ruby-concurrent

Package

Name
ruby-concurrent
Purl
pkg:deb/ubuntu/ruby-concurrent?arch=source&distro=xenial

Affected ranges

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

Affected versions

1.*
1.0.0-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "ruby-concurrent",
            "binary_version": "1.0.0-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54906.json"
Ubuntu:18.04:LTS
ruby-concurrent

Package

Name
ruby-concurrent
Purl
pkg:deb/ubuntu/ruby-concurrent?arch=source&distro=bionic

Affected ranges

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

Affected versions

1.*
1.0.5-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "ruby-concurrent",
            "binary_version": "1.0.5-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54906.json"
Ubuntu:20.04:LTS
ruby-concurrent

Package

Name
ruby-concurrent
Purl
pkg:deb/ubuntu/ruby-concurrent?arch=source&distro=focal

Affected ranges

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

Affected versions

1.*
1.0.5-3
1.0.5-4
1.1.6+dfsg-2
1.1.6+dfsg-3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "ruby-concurrent",
            "binary_version": "1.1.6+dfsg-3"
        },
        {
            "binary_name": "ruby-concurrent-ext",
            "binary_version": "1.1.6+dfsg-3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54906.json"
Ubuntu:22.04:LTS
ruby-concurrent

Package

Name
ruby-concurrent
Purl
pkg:deb/ubuntu/ruby-concurrent?arch=source&distro=jammy

Affected ranges

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

Affected versions

1.*
1.1.6+dfsg-3
1.1.6+dfsg-3build1
1.1.6+dfsg-4

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "ruby-concurrent",
            "binary_version": "1.1.6+dfsg-4"
        },
        {
            "binary_name": "ruby-concurrent-ext",
            "binary_version": "1.1.6+dfsg-4"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54906.json"
Ubuntu:24.04:LTS
ruby-concurrent

Package

Name
ruby-concurrent
Purl
pkg:deb/ubuntu/ruby-concurrent?arch=source&distro=noble

Affected ranges

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

Affected versions

1.*
1.1.6+dfsg-5build2
1.1.6+dfsg-5build3
1.2.3-2build1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "ruby-concurrent",
            "binary_version": "1.2.3-2build1"
        },
        {
            "binary_name": "ruby-concurrent-ext",
            "binary_version": "1.2.3-2build1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54906.json"
Ubuntu:25.10
ruby-concurrent

Package

Name
ruby-concurrent
Purl
pkg:deb/ubuntu/ruby-concurrent?arch=source&distro=questing

Affected ranges

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

Affected versions

1.*
1.3.4-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "ruby-concurrent",
            "binary_version": "1.3.4-1"
        },
        {
            "binary_name": "ruby-concurrent-ext",
            "binary_version": "1.3.4-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54906.json"
Ubuntu:26.04:LTS
ruby-concurrent

Package

Name
ruby-concurrent
Purl
pkg:deb/ubuntu/ruby-concurrent?arch=source&distro=resolute

Affected ranges

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

Affected versions

1.*
1.3.4-1
1.3.6-1

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "ruby-concurrent",
            "binary_version": "1.3.6-1"
        },
        {
            "binary_name": "ruby-concurrent-ext",
            "binary_version": "1.3.6-1"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54906.json"