CVE-2026-34909: Ubiquiti UniFi OS Path Traversal Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 32 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 68%
EPSS score, percentile 99.3 of all scored records
- How severe?
- 10.0 Critical
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA deadline . Apply mitigations in accordance with vendor instructions … Full text
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- before 5.0.8
- before 4.0.14
- before 5.1.12
- before 5.1.12
- before 5.1.12
- before 5.1.12
and 14 more in the table below
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
CISA due date for this action: .
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://community.ui.com/releases/Security-Advisory-Bulletin-064-064/84811c09-4cf4-42ab-bd61-cc994445963b
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-34909
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 5.0.8 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 4.0.14 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.11 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | before 5.1.12 |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
Ubiquiti UniFi OS contains a path traversal vulnerability which could allow a malicious actor with access to the network to access files on the underlying system that could be manipulated to access an underlying account.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2026-34909 to its Known Exploited Vulnerabilities (KEV) catalog on 23 Jun 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 26 Jun 2026.
- The CVE record was published on 22 May 2026, 32 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 10.0 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 68% (percentile 99.3), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to access files on the underlying system that could be manipulated to access an underlying account.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-22: Path Traversal
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CVE record last updated | |
| CISA due date for the required action |
References
More exploited Ubiquiti vulnerabilities
- CVE-2026-34908: Ubiquiti UniFi OS Improper Access Control Vulnerability
- CVE-2026-34910: Ubiquiti UniFi OS Improper Input Validation Vulnerability
- CVE-2010-5330: Ubiquiti AirOS Command Injection Vulnerability