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Fencer Intel
high 7.5

CVE-2026-58250 json

NATS Server: Pre-auth server crash via double INFO in leafnode handshake

published 4mo ago modified 17d ago also BIT-nats-2026-58250 , EUVD-2026-42380 , GHSA-3g5q-cfh2-cq67 , JLSEC-2026-1150

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 55%
public exploits
0
none known

Summary

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.12.8 and 2.11.17, an unauthenticated peer with network access to a leafnode listener with compression enabled could crash the server during the pre-authentication leafnode handshake by sending repeated leafnode INFO protocol messages before authentication and account setup completed. This issue is fixed in versions 2.12.8 and 2.11.17.

Patch / fix

  • bitnami nats 2.11.17, 2.12.8
  • julia nats_server_jll 2.14.3+0
  • linuxfoundation nats-server 2.11.17, 2.12.8
  • nats nats_server 2.11.17, 2.12.8
  • nats nats_streaming_server 2.11.17, 2.12.8
  • nats-server Debian 14 2.14.1-1

debian advisories DEBIAN-CVE-2026-58250

  • telegraf Azure Linux 3.0 1.31.0-27

azure linux advisories AZL-92250

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-58250 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-58250 updated cvss 7.5

github.com/nats-io/nats-server: NATS Server: Denial of Service via repeated leafnode INFO messages during pre-authentication

  • Red Hat Hardened Images nats-server2.12, nats-server2.14
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
4mo ago

Exploit prediction

0.74% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami nats
<2.11.17
>=2.12.0, <2.12.8
2.11.17
2.12.8
julia nats_server_jll
<2.14.3+0
2.14.3+0

Affected products

  • nats-io nats-server

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.