DEBIAN-CVE-2026-27571
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The WebSockets handling of NATS messages handles compressed messages via the WebSockets negotiated compression. Prior to versions 2.11.2 and 2.12.3, the implementation bound the memory size of a NATS message but did not independently bound the memory consumption of the memory stream when constructing a NATS message which might then fail validation for size reasons. An attacker can use a compression bomb to cause excessive memory consumption, often resulting in the operating system terminating the server process. The use of compression is negotiated before authentication, so this does not require valid NATS credentials to exploit. The fix, present in versions 2.11.2 and 2.12.3, was to bounds the decompression to fail once the message was too large, instead of continuing on. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points.
DEBIAN-CVE-2026-27571
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-2026-27571
nats-server
Source reference: /affected/0/package/name
- Affected versions
- 2.10.1-1
Source reference:
/affected/0/versions2.10.16-1Source reference:
/affected/0/versions2.10.18-1Source reference:
/affected/0/versions2.10.24-1Source reference:
/affected/0/versions2.10.27-1Source reference:
/affected/0/versions2.10.3-1Source reference:
/affected/0/versions2.10.4-1Source reference:
/affected/0/versions2.10.7-1Source reference:
/affected/0/versions2.12.4-1Source reference:
/affected/0/versions2.12.6-1Source reference:
/affected/0/versions2.14.1-1Source reference:
/affected/0/versions2.14.3-1Source reference:
/affected/0/versions2.14.6-1Source reference:
/affected/0/versions2.9.10-1Source reference:
/affected/0/versions2.9.19-1Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
nats-server
Source reference: /affected/1/package/name
- Affected versions
- 2.10.27-1
Source reference:
/affected/1/versions2.12.4-1Source reference:
/affected/1/versions2.12.6-1Source reference:
/affected/1/versions2.14.1-1Source reference:
/affected/1/versions2.14.3-1Source reference:
/affected/1/versions2.14.6-1Source reference:
/affected/1/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
nats-server
Source reference: /affected/2/package/name
- Affected versions
- 2.10.27-1
Source reference:
/affected/2/versions - Fixed versions
- 2.12.4-1
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": "nats-server",
"purl": "pkg:deb/debian/nats-server?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"2.10.1-1",
"2.10.16-1",
"2.10.18-1",
"2.10.24-1",
"2.10.27-1",
"2.10.3-1",
"2.10.4-1",
"2.10.7-1",
"2.12.4-1",
"2.12.6-1",
"2.14.1-1",
"2.14.3-1",
"2.14.6-1",
"2.9.10-1",
"2.9.19-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-27571.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nats-server",
"purl": "pkg:deb/debian/nats-server?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.10.27-1",
"2.12.4-1",
"2.12.6-1",
"2.14.1-1",
"2.14.3-1",
"2.14.6-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-27571.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.12.4-1"
}
]
}
],
"package": {
"name": "nats-server",
"purl": "pkg:deb/debian/nats-server?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.10.27-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-27571.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #56683 · Revision 1
- Added to Heist Feed
- Publisher date