CVE-2026-58207
Description
A flaw was found in NATS Server. A client with the ability to send account-scoped connection monitoring requests could crash the server. This is achieved by providing pagination offset and limit values that cause an arithmetic overflow, leading to a Denial of Service (DoS).
Statement
CVE.org and NVD independently assess this issue at different severities than Red Hat because CVE.org uses a Changed scope (S:C) in its CVSS vector, treating the crash as impacting components beyond the NATS Server process itself. Red Hat, consistent with NVDs own scoring, assesses the impact as scoped to the NATS Server process (Scope Unchanged), resulting in a CVSS score of 6.5 and a Moderate impact rating. Only account-scoped connection-monitoring requests can trigger the arithmetic overflow, and no Red Hat product runs an externally-reachable, unauthenticated NATS Server monitoring endpoint by default.
Mitigation
Upstream mitigation: restrict publish access to system request subjects (e.g. \.REQ.ACCOUNT.*.CONNZ) for untrusted clients, and avoid no-auth NATS deployments where untrusted clients can publish to system monitoring request subjects. Upgrading to nats-server 2.14.3 or 2.12.12 (or later) fully resolves the issue.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | 6.5 | 7.7 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Changed |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Memory); DoS: Instability
This weakness can generally lead to undefined behavior and therefore crashes. When the calculated result is used for resource allocation, this weakness can cause too many (or too few) resources to be allocated, possibly enabling crashes if the product requests more resources than can be provided.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the overflow/wraparound results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows, which can be used to execute arbitrary code. This is usually outside the scope of the product's implicit security policy.
Availability,Other
Technical Impact: Alter Execution Logic; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
If the overflow/wraparound occurs in a loop index variable, this could cause the loop to terminate at the wrong time - too early, too late, or not at all (i.e., infinite loops). With too many iterations, some loops could consume too many resources such as memory, file handles, etc., possibly leading to a crash or other DoS.
Access Control
Technical Impact: Bypass Protection Mechanism
If integer values are used in security-critical decisions, such as calculating quotas or allocation limits, integer overflows can be used to cause an incorrect security decision.
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