CVE-2026-58250Public exploitNetwork attack vector

Pre-authentication crash via repeated leafnode INFO messages

Published Jul 8, 2026 · Updated Jul 8, 2026

NULL pointer dereference in NATS Server before 2.11.17 and 2.12.0-preview.1 through 2.12.7 allows remote attackers to crash the server. During compression negotiation, processLeafnodeInfo accepts a second pre-CONNECT INFO message and later dereferences nil c.acc or c.leaf.remote state. Network access to a compression-enabled leafnode listener is sufficient before authentication, and exploitation panics the server process without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability0.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

NULL pointer dereference in NATS Server before 2.11.17 and 2.12.0-preview.1 through 2.12.7 allows remote attackers to crash the server. During compression negotiation, processLeafnodeInfo accepts a second pre-CONNECT INFO message and later dereferences nil c.acc or c.leaf.remote state. Network access to a compression-enabled leafnode listener is sufficient before authentication, and exploitation panics the server process without reported data disclosure or modification.

The record

CVE
CVE-2026-58250
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
NATS
Product
NATS Server
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.11.17
  2. Affected versionversion=>= 2.12.0-preview.1, < 2.12.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NATS · NATS Serverversion=< 2.11.17; version=>= 2.12.0-preview.1, < 2.12.8

Published CVSS scores

8.6GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
7.5GitHub CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo