Vulnerable Library - concurrent-ruby-1.3.3.gem
Modern concurrency tools including agents, futures, promises, thread pools, actors, supervisors, and more.
Inspired by Erlang, Clojure, Go, JavaScript, actors, and classic concurrency patterns.
Library home page: https://rubygems.org/gems/concurrent-ruby-1.3.3.gem
Path to dependency file: /example/Gemfile.lock
Path to vulnerable library: /example/Gemfile.lock
Found in HEAD commit: 3db7a414c18649ac89b74bbea1ae5f8072fd142d
Vulnerabilities
**In some cases, Remediation PR cannot be created automatically for a vulnerability despite the availability of remediation
Details
CVE-2026-54904
Vulnerable Library - concurrent-ruby-1.3.3.gem
Modern concurrency tools including agents, futures, promises, thread pools, actors, supervisors, and more.
Inspired by Erlang, Clojure, Go, JavaScript, actors, and classic concurrency patterns.
Library home page: https://rubygems.org/gems/concurrent-ruby-1.3.3.gem
Path to dependency file: /example/Gemfile.lock
Path to vulnerable library: /example/Gemfile.lock
Dependency Hierarchy:
- ❌ concurrent-ruby-1.3.3.gem (Vulnerable Library)
Found in HEAD commit: 3db7a414c18649ac89b74bbea1ae5f8072fd142d
Found in base branch: main
Vulnerability Details
concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::AtomicReference#update can enter a permanent busy retry loop when the current value is Float::NAN. The issue is caused by the interaction between AtomicReference#update, which retries until compare_and_set(old_value, new_value) succeeds; Numeric compare_and_set, which checks old == old_value before attempting the underlying atomic swap.; and Ruby NaN semantics, where Float::NAN == Float::NAN is always false. As a result, once an AtomicReference contains Float::NAN, calling #update repeatedly evaluates the caller's block and never returns. In services that store externally derived numeric values in an AtomicReference, this can cause CPU exhaustion or permanent request/job hangs. This vulnerability is fixed in 1.3.7.
Publish Date: 2026-06-24
URL: CVE-2026-54904
CVSS 3 Score Details (7.5)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: None
- Availability Impact: High
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Origin: ruby-concurrency/concurrent-ruby@6e37e06
Release Date: 2026-06-19
Fix Resolution: https://github.com/ruby-concurrency/concurrent-ruby.git - v1.3.7
⛑️ Automatic Remediation will be attempted for this issue.
CVE-2026-54905
Vulnerable Library - concurrent-ruby-1.3.3.gem
Modern concurrency tools including agents, futures, promises, thread pools, actors, supervisors, and more.
Inspired by Erlang, Clojure, Go, JavaScript, actors, and classic concurrency patterns.
Library home page: https://rubygems.org/gems/concurrent-ruby-1.3.3.gem
Path to dependency file: /example/Gemfile.lock
Path to vulnerable library: /example/Gemfile.lock
Dependency Hierarchy:
- ❌ concurrent-ruby-1.3.3.gem (Vulnerable Library)
Found in HEAD commit: 3db7a414c18649ac89b74bbea1ae5f8072fd142d
Found in base branch: main
Vulnerability Details
concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::ReentrantReadWriteLock can incorrectly grant a write lock after one thread acquires the read lock 32,768 times. The lock stores a thread's local read and write hold counts in one integer. The low 15 bits are used for the read hold count, and bit 15 is used as WRITE_LOCK_HELD. After 32,768 reentrant read acquisitions, the local read count crosses into the write-lock bit. try_write_lock then treats the thread as already holding a write lock and returns true without setting the global RUNNING_WRITER bit. This breaks the core mutual-exclusion guarantee: the caller is told it has a write lock, but other threads can still hold or acquire read locks at the same time. This vulnerability is fixed in 1.3.7.
Publish Date: 2026-06-24
URL: CVE-2026-54905
CVSS 3 Score Details (5.3)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Local
- Attack Complexity: Low
- Privileges Required: Low
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: Low
- Availability Impact: Low
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Origin: ruby-concurrency/concurrent-ruby@7e4d711
Release Date: 2026-06-19
Fix Resolution: https://github.com/ruby-concurrency/concurrent-ruby.git - v1.3.7
⛑️ Automatic Remediation will be attempted for this issue.
CVE-2026-54906
Vulnerable Library - concurrent-ruby-1.3.3.gem
Modern concurrency tools including agents, futures, promises, thread pools, actors, supervisors, and more.
Inspired by Erlang, Clojure, Go, JavaScript, actors, and classic concurrency patterns.
Library home page: https://rubygems.org/gems/concurrent-ruby-1.3.3.gem
Path to dependency file: /example/Gemfile.lock
Path to vulnerable library: /example/Gemfile.lock
Dependency Hierarchy:
- ❌ concurrent-ruby-1.3.3.gem (Vulnerable Library)
Found in HEAD commit: 3db7a414c18649ac89b74bbea1ae5f8072fd142d
Found in base branch: main
Vulnerability Details
concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::ReadWriteLock#release_write_lock 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#release_read_lock 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.
Publish Date: 2026-06-24
URL: CVE-2026-54906
CVSS 3 Score Details (4.0)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Local
- Attack Complexity: High
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: Low
- Availability Impact: Low
For more information on CVSS3 Scores, click here.
Suggested Fix
Type: Upgrade version
Origin: ruby-concurrency/concurrent-ruby@3fd4932
Release Date: 2026-06-19
Fix Resolution: https://github.com/ruby-concurrency/concurrent-ruby.git - v1.3.7
⛑️ Automatic Remediation will be attempted for this issue.
⛑️Automatic Remediation will be attempted for this issue.
Modern concurrency tools including agents, futures, promises, thread pools, actors, supervisors, and more. Inspired by Erlang, Clojure, Go, JavaScript, actors, and classic concurrency patterns.
Library home page: https://rubygems.org/gems/concurrent-ruby-1.3.3.gem
Path to dependency file: /example/Gemfile.lock
Path to vulnerable library: /example/Gemfile.lock
Found in HEAD commit: 3db7a414c18649ac89b74bbea1ae5f8072fd142d
Vulnerabilities
**In some cases, Remediation PR cannot be created automatically for a vulnerability despite the availability of remediation
Details
Vulnerable Library - concurrent-ruby-1.3.3.gem
Modern concurrency tools including agents, futures, promises, thread pools, actors, supervisors, and more. Inspired by Erlang, Clojure, Go, JavaScript, actors, and classic concurrency patterns.
Library home page: https://rubygems.org/gems/concurrent-ruby-1.3.3.gem
Path to dependency file: /example/Gemfile.lock
Path to vulnerable library: /example/Gemfile.lock
Dependency Hierarchy:
Found in HEAD commit: 3db7a414c18649ac89b74bbea1ae5f8072fd142d
Found in base branch: main
Vulnerability Details
concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::AtomicReference#update can enter a permanent busy retry loop when the current value is Float::NAN. The issue is caused by the interaction between AtomicReference#update, which retries until compare_and_set(old_value, new_value) succeeds; Numeric compare_and_set, which checks old == old_value before attempting the underlying atomic swap.; and Ruby NaN semantics, where Float::NAN == Float::NAN is always false. As a result, once an AtomicReference contains Float::NAN, calling #update repeatedly evaluates the caller's block and never returns. In services that store externally derived numeric values in an AtomicReference, this can cause CPU exhaustion or permanent request/job hangs. This vulnerability is fixed in 1.3.7.
Publish Date: 2026-06-24
URL: CVE-2026-54904
CVSS 3 Score Details (7.5)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: None
- Availability Impact: High
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Origin: ruby-concurrency/concurrent-ruby@6e37e06
Release Date: 2026-06-19
Fix Resolution: https://github.com/ruby-concurrency/concurrent-ruby.git - v1.3.7
⛑️ Automatic Remediation will be attempted for this issue.
Vulnerable Library - concurrent-ruby-1.3.3.gem
Modern concurrency tools including agents, futures, promises, thread pools, actors, supervisors, and more. Inspired by Erlang, Clojure, Go, JavaScript, actors, and classic concurrency patterns.
Library home page: https://rubygems.org/gems/concurrent-ruby-1.3.3.gem
Path to dependency file: /example/Gemfile.lock
Path to vulnerable library: /example/Gemfile.lock
Dependency Hierarchy:
Found in HEAD commit: 3db7a414c18649ac89b74bbea1ae5f8072fd142d
Found in base branch: main
Vulnerability Details
concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::ReentrantReadWriteLock can incorrectly grant a write lock after one thread acquires the read lock 32,768 times. The lock stores a thread's local read and write hold counts in one integer. The low 15 bits are used for the read hold count, and bit 15 is used as WRITE_LOCK_HELD. After 32,768 reentrant read acquisitions, the local read count crosses into the write-lock bit. try_write_lock then treats the thread as already holding a write lock and returns true without setting the global RUNNING_WRITER bit. This breaks the core mutual-exclusion guarantee: the caller is told it has a write lock, but other threads can still hold or acquire read locks at the same time. This vulnerability is fixed in 1.3.7.
Publish Date: 2026-06-24
URL: CVE-2026-54905
CVSS 3 Score Details (5.3)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Local
- Attack Complexity: Low
- Privileges Required: Low
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: Low
- Integrity Impact: Low
- Availability Impact: Low
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Origin: ruby-concurrency/concurrent-ruby@7e4d711
Release Date: 2026-06-19
Fix Resolution: https://github.com/ruby-concurrency/concurrent-ruby.git - v1.3.7
⛑️ Automatic Remediation will be attempted for this issue.
Vulnerable Library - concurrent-ruby-1.3.3.gem
Modern concurrency tools including agents, futures, promises, thread pools, actors, supervisors, and more. Inspired by Erlang, Clojure, Go, JavaScript, actors, and classic concurrency patterns.
Library home page: https://rubygems.org/gems/concurrent-ruby-1.3.3.gem
Path to dependency file: /example/Gemfile.lock
Path to vulnerable library: /example/Gemfile.lock
Dependency Hierarchy:
Found in HEAD commit: 3db7a414c18649ac89b74bbea1ae5f8072fd142d
Found in base branch: main
Vulnerability Details
concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::ReadWriteLock#release_write_lock 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#release_read_lock 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.
Publish Date: 2026-06-24
URL: CVE-2026-54906
CVSS 3 Score Details (4.0)
Base Score Metrics:
- Exploitability Metrics:
- Attack Vector: Local
- Attack Complexity: High
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Impact Metrics:
- Confidentiality Impact: None
- Integrity Impact: Low
- Availability Impact: Low
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Origin: ruby-concurrency/concurrent-ruby@3fd4932
Release Date: 2026-06-19
Fix Resolution: https://github.com/ruby-concurrency/concurrent-ruby.git - v1.3.7
⛑️ Automatic Remediation will be attempted for this issue.
⛑️Automatic Remediation will be attempted for this issue.