Answer in brief
CVE-2026-58254 records a Medium severity (CVSS 5.3) vulnerability in NATS Server: Incomplete fix for CVE-2026-33249: Leaf node connections bypass Nats-Trace-Dest permission check. The current sources do not mark it as known exploited. The current feed maps nats-io/nats-server (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps nats-io/nats-server (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| nats-io/nats-servergeneric | < 2.12.8 || >= 2.14.0-RC.1, < 2.14.3 | Not reported |
Published upstream
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 8, 2026
NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.8, message trace destination checks were applied to ordinary client connections but not consistently to messages arriving through leafnode connections, allowing a leafnode operator to send trace events to subjects that would not otherwise be permitted and to use trace-only behavior to prevent normal delivery or storage of affected messages. This issue is fixed in versions 2.14.3 and 2.12.8.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-58254 records a Medium severity (CVSS 5.3) vulnerability in NATS Server: Incomplete fix for CVE-2026-33249: Leaf node connections bypass Nats-Trace-Dest permission check. The current sources do not mark it as known exploited. The current feed maps nats-io/nats-server (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps nats-io/nats-server (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| nats-io/nats-servergeneric | < 2.12.8 || >= 2.14.0-RC.1, < 2.14.3 | Not reported |
Published upstream
Jul 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 8, 2026
NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.8, message trace destination checks were applied to ordinary client connections but not consistently to messages arriving through leafnode connections, allowing a leafnode operator to send trace events to subjects that would not otherwise be permitted and to use trace-only behavior to prevent normal delivery or storage of affected messages. This issue is fixed in versions 2.14.3 and 2.12.8.
Quoted source text, attributed separately from HOL analysis.