UBUNTU-CVE-2026-27571

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Source

https://ubuntu.com/security/CVE-2026-27571

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27571.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-27571

Upstream

CVE-2026-27571

Published

2026-02-24T17:29:00Z

Modified

2026-03-02T12:12:31.144101Z

Severity

5.9 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Ubuntu - medium

Summary

[none]

Details

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.

References

Affected packages

Ubuntu:24.04:LTS / nats-server

Package

Name: nats-server
Purl: pkg:deb/ubuntu/nats-server@2.10.7-1ubuntu0.3?arch=source&distro=noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

2.*

2.9.19-1build1

2.10.3-1

2.10.4-1

2.10.7-1

2.10.7-1ubuntu0.1

2.10.7-1ubuntu0.2

2.10.7-1ubuntu0.3

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "golang-github-nats-io-nats-server-dev",
            "binary_version": "2.10.7-1ubuntu0.3"
        },
        {
            "binary_name": "nats-server",
            "binary_version": "2.10.7-1ubuntu0.3"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-27571.json"

Ubuntu:25.10 / nats-server