CVE-2023-27992
Confirmed PUBLISHEDThe pre-authentication command injection vulnerability in the Zyxel NAS326 firmware versions prior to V5.21(AAZF.14)C0, NAS540 firmware...
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
The 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.
- CVE Published
- Jun 19, 2023
- Exploitation Reported
- Jun 23, 2023
- CVSS
- 9.8 Critical
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Zyxel |
NAS326 firmware
|
< V5.21(AAZF.14)C0 |
Affected |
| Zyxel |
NAS540 firmware
|
< V5.21(AATB.11)C0 |
Affected |
| Zyxel |
NAS542 firmware
|
< V5.21(ABAG.11)C0 |
Affected |
CVE References
- zyxel.com/global/en/support/security-advisories/zyxel-... zyxel.com · CVE Record https://www.zyxel.com/global/en/support/security-advisories/zyxel-sec...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2023-06-23 00:00 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitation Status
Exploited in the wild
Recorded 2023-06-23 00:00:00 UTC · CISA
Weaknesses (CWE)
-
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Scanner Integrations
| Scanner | Reference | Detected |
|---|---|---|
| Nessus | https://www.tenable.com/plugins/nessus/200304 | Jun 02, 2025 |
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
09:26 UTC about 1 year ago09:26 UTC · about 1 year ago
Nessus plugin available
Scanner coverage available
-
00:00 UTC about 3 years ago00:00 UTC · about 3 years ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
11:42 UTC about 3 years ago11:42 UTC · about 3 years ago
CVE published
Vulnerability disclosed publicly
-
08:44 UTC over 3 years ago08:44 UTC · over 3 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2023-27992
{
"cve_id": "CVE-2023-27992",
"title": "The pre-authentication command injection vulnerability in the Zyxel NAS326 fi...",
"affected_vendor": "Zyxel",
"affected_product": "NAS326 firmware, NAS540 firmware, NAS542 firmware",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.8,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}