DEBIAN-CVE-2026-54904
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.
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/versions1.2.3-1Source reference:
/affected/0/versions1.2.3-2Source reference:
/affected/0/versions1.2.3-3Source reference:
/affected/0/versions1.2.3-4Source reference:
/affected/0/versions1.3.4-1Source reference:
/affected/0/versions1.3.4-1~exp1Source reference:
/affected/0/versions1.3.5-1Source reference:
/affected/0/versions1.3.6-1Source reference:
/affected/0/versions1.3.7-1Source reference:
/affected/0/versions1.3.7-2Source reference:
/affected/0/versions1.3.7-3Source reference:
/affected/0/versions1.3.7-4Source reference:
/affected/0/versions1.3.8-1Source 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/versions1.3.6-1Source reference:
/affected/1/versions1.3.7-1Source reference:
/affected/1/versions1.3.7-2Source reference:
/affected/1/versions1.3.7-3Source reference:
/affected/1/versions1.3.7-4Source reference:
/affected/1/versions1.3.8-1Source 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/versions1.3.6-1Source 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
- Added to Heist Feed
- Publisher date