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Advisory severityHigh7.5Red Hat Linux

High [CVE-2026-58250] Denial of Service via repeated leafnode INFO messages during pre-authentication

This high-severity Red Hat Linux advisory covers CVE-2026-58250.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-58250 Source published Source updated

VulniPulse record published Record updated

CVE-2026-58250
Affected products & platforms
Red Hat LinuxUnclassified
Open source advisory

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.

This leads to a Denial of Service (DoS), making the server unavailable to legitimate users. This is an Important denial of service vulnerability in NATS Server.

Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-476.

Red Hat lists Red Hat Hardened Images as not affected.

Is CVE-2026-58250 exploited?

No exploitation is reported in the sources VulniPulse tracks: CVE-2026-58250 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.

How do I fix CVE-2026-58250?

Upgrade to a fixed release named by Red Hat:

  • 2.12.8
  • 2.11.17

Confirm against the vendor advisory before you patch.

Affected versions
  • < 2.12.8
  • < 2.11.17

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

Fixed versions
  • 2.12.8
  • 2.11.17

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • To reduce exposure, disable compression on NATS Server leafnode listeners if not strictly required for your environment. Alternatively, implement network access controls to restrict connectivity to leafnode listeners to only trusted clients. This limits the ability of unauthenticated peers to initiate the vulnerable handshake.

Official advisory · high-confidence parse· fetched 11 days ago·verify at source

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