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DEBIAN-CVE-2026-54904

Type: advisorySource: OSV1 source record

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.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-54904

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:DEBIAN-CVE-2026-54904

ruby-concurrent

Source reference: /affected/0/package/name

Affected versions
1.1.6+dfsg-5

Source reference: /affected/0/versions

1.2.3-1

Source reference: /affected/0/versions

1.2.3-2

Source reference: /affected/0/versions

1.2.3-3

Source reference: /affected/0/versions

1.2.3-4

Source reference: /affected/0/versions

1.3.4-1

Source reference: /affected/0/versions

1.3.4-1~exp1

Source reference: /affected/0/versions

1.3.5-1

Source reference: /affected/0/versions

1.3.6-1

Source reference: /affected/0/versions

1.3.7-1

Source reference: /affected/0/versions

1.3.7-2

Source reference: /affected/0/versions

1.3.7-3

Source reference: /affected/0/versions

1.3.7-4

Source reference: /affected/0/versions

1.3.8-1

Source reference: /affected/0/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

ruby-concurrent

Source reference: /affected/1/package/name

Affected versions
1.3.5-1

Source reference: /affected/1/versions

1.3.6-1

Source reference: /affected/1/versions

1.3.7-1

Source reference: /affected/1/versions

1.3.7-2

Source reference: /affected/1/versions

1.3.7-3

Source reference: /affected/1/versions

1.3.7-4

Source reference: /affected/1/versions

1.3.8-1

Source reference: /affected/1/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

ruby-concurrent

Source reference: /affected/2/package/name

Affected versions
1.3.5-1

Source reference: /affected/2/versions

1.3.6-1

Source reference: /affected/2/versions

Fixed versions
1.3.7-1

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "ruby-concurrent",
      "purl": "pkg:deb/debian/ruby-concurrent?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "1.1.6+dfsg-5",
      "1.2.3-1",
      "1.2.3-2",
      "1.2.3-3",
      "1.2.3-4",
      "1.3.4-1",
      "1.3.4-1~exp1",
      "1.3.5-1",
      "1.3.6-1",
      "1.3.7-1",
      "1.3.7-2",
      "1.3.7-3",
      "1.3.7-4",
      "1.3.8-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54904.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "ruby-concurrent",
      "purl": "pkg:deb/debian/ruby-concurrent?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "1.3.5-1",
      "1.3.6-1",
      "1.3.7-1",
      "1.3.7-2",
      "1.3.7-3",
      "1.3.7-4",
      "1.3.8-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54904.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.3.7-1"
          }
        ]
      }
    ],
    "package": {
      "name": "ruby-concurrent",
      "purl": "pkg:deb/debian/ruby-concurrent?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "1.3.5-1",
      "1.3.6-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-54904.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#55909 · Revision 1
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Publisher date
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