CVE-2026-29785Public exploitNetwork attack vector

Pre-authentication crash via pre-CONNECT leaf subscription command

Published Mar 25, 2026 · Updated Mar 25, 2026

NULL pointer dereference in NATS Server before 2.11.14 and 2.12.0-RC.1 through 2.12.4 allows remote attackers to crash the server. The leafnode protocol accepts LS+ or LS- before CONNECT initializes the client account, then dereferences the nil account while processing the command. The leafnode listener and compression must be enabled; no authentication is required, and the resulting panic interrupts the service.

CVSS severity7.5
High
EPSS probability0.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in NATS Server before 2.11.14 and 2.12.0-RC.1 through 2.12.4 allows remote attackers to crash the server. The leafnode protocol accepts LS+ or LS- before CONNECT initializes the client account, then dereferences the nil account while processing the command. The leafnode listener and compression must be enabled; no authentication is required, and the resulting panic interrupts the service.

The record

CVE
CVE-2026-29785
Published
Mar 25, 2026
Updated
Mar 25, 2026
Vendor
NATS.io
Product
NATS Server
Classifications
CWE-409, CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 25, 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=< 2.11.14
  2. Affected versionversion=>= 2.12.0-RC.1, < 2.12.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

NATS.io · NATS Serverversion=< 2.11.14; version=>= 2.12.0-RC.1, < 2.12.5

Published CVSS scores

7.5GitHub, Inc.CVSS: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-409Improper Handling of Highly Compressed Data (Data Amplification)
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

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Your stack

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