Answer in brief
CVE-2023-27992 records a High severity vulnerability in CVE Program Container. The current sources mark it as known exploited. The current feed maps Zyxel/NAS326 firmware (generic), Zyxel/NAS540 firmware (generic), Zyxel/NAS542 firmware (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. Known-exploitation status makes exposure review time-sensitive. 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 Zyxel/NAS326 firmware (generic), Zyxel/NAS540 firmware (generic), Zyxel/NAS542 firmware (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Zyxel/NAS326 firmwaregeneric | < V5.21(AAZF.14)C0 | Not reported |
| Zyxel/NAS540 firmwaregeneric | < V5.21(AATB.11)C0 | Not reported |
| Zyxel/NAS542 firmwaregeneric | < V5.21(ABAG.11)C0 | Not reported |
Published upstream
Jun 19, 2023
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2025
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
May 24, 2026
Added to CISA KEV
Jun 23, 2023
Evidence: source:kev:kev:kev:recordThe pre-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.14)C0, NAS540 firmware versions prior to V5.21(AATB.11)C0, and NAS542 firmware versions prior to V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands remotely by sending a crafted HTTP request.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2023-27992 records a High severity vulnerability in CVE Program Container. The current sources mark it as known exploited. The current feed maps Zyxel/NAS326 firmware (generic), Zyxel/NAS540 firmware (generic), Zyxel/NAS542 firmware (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. Known-exploitation status makes exposure review time-sensitive. 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 Zyxel/NAS326 firmware (generic), Zyxel/NAS540 firmware (generic), Zyxel/NAS542 firmware (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Zyxel/NAS326 firmwaregeneric | < V5.21(AAZF.14)C0 | Not reported |
| Zyxel/NAS540 firmwaregeneric | < V5.21(AATB.11)C0 | Not reported |
| Zyxel/NAS542 firmwaregeneric | < V5.21(ABAG.11)C0 | Not reported |
Published upstream
Jun 19, 2023
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2025
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
May 24, 2026
Added to CISA KEV
Jun 23, 2023
Evidence: source:kev:kev:kev:recordThe pre-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.14)C0, NAS540 firmware versions prior to V5.21(AATB.11)C0, and NAS542 firmware versions prior to V5.21(ABAG.11)C0 could allow an unauthenticated attacker to execute some operating system (OS) commands remotely by sending a crafted HTTP request.
Quoted source text, attributed separately from HOL analysis.