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Full vulnerability report · 2026
CVE-2026-34910High confidence

Ubiquiti UniFi OS Improper Input Validation Vulnerability

Ubiquiti · UniFi OS

10.0CriticalCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2026-06-26 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • CISA confirms exploitation in the wild.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 45.77% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Ubiquiti UniFi OS and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-31382

CISA KEV mirrored by ENISA

A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 23 Jun 2026. Evidence sources: cisa_kev.
ENISA score
10.0 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2026-06-26 as the remediation due date.

Patch available
01

What, why and how

Ubiquiti UniFi OS contains an improper input validation vulnerability which could allow a malicious actor with access to the network to conduct command injection.

What

Ubiquiti UniFi OS contains an improper input validation vulnerability which could allow a malicious actor with access to the network to conduct command injection.

Why

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Ubiquiti UniFi OS contains an improper input validation vulnerability which could allow a malicious actor with access to the network to conduct command injection.

Why

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-06-23.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Improper Input Validation → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-20 ↗

CWE-20: Improper Input Validation. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-20CISA KEVPublic exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-31382Known-exploited evidence recorded

A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection.

Official EUVD record ↗
BSI · German · WID-SEC-2026-1639Ubiquiti UniFi OS Server: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Ubiquiti UniFi OS Server ausnutzen, um beliebigen Programmcode auszuführen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder vertrauliche Informationen offenzulegen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-498Ubiquiti security advisory (AV26-498) – Update 1

On May 21, 2026, Ubiquiti published a security advisory to address vulnerabilities in the following products. Included were critical updates for the following: Update 1 On June 23, 2026, Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2026-34908, CVE-2026-34909, and CVE-2026-34910 to their Known Exploited Vulnerabilities (KEV) Database.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260527Security Bulletin 27 May 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 27 May 2026, published on 27 May 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-020869UIのEnterprise Fortress Gateway Firmware (EFG)等の複数製品におけるアクセス制御に関する脆弱性

ネットワークへのアクセス権を持つ悪意のある人物が、UniFi OSデバイスに存在する不適切なアクセス制御の脆弱性を悪用し、システムに対して不正な変更を加える可能性があります。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-020868UIのEnterprise Fortress Gateway Firmware (EFG)等の複数製品におけるパストラバーサルの脆弱性

ネットワークにアクセスできる悪意のある攻撃者は、UniFi OSデバイスに見つかったパストラバーサルの脆弱性を悪用し、基盤となるシステム上のファイルにアクセスできます。そして、そのファイルを操作することで基盤となるアカウントにアクセスされる可能性があります。

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-020867UIのEnterprise Fortress Gateway Firmware (EFG)等の複数製品における入力確認に関する脆弱性

ネットワークにアクセスできる悪意のある攻撃者は、UniFi OS デバイスに存在する不適切な入力検証の脆弱性を悪用し、コマンドインジェクションを実行する可能性があります。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6871Ubiquiti 제품 보안 업데이트 권고

UniFi OS에서 발생하는 Improper Input Validation 취약점(CVE-2026-34910) [1][5]

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6856美 CISA 발표 주요 Exploit 정보공유(Update. 2026-06-23)

Ubiquiti UniFi OS Improper Input Validation Vulnerability

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 22 May 2026 · Last source change 24 Jun 2026, 03:55 UTC · CWE-20 · Improper Input Validation

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-31382
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    < 5.0.8; < 5.1.12; < 5.1.11 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    UniFi OS Server: < 5.0.8; UDM: < 5.1.12; UDM-Pro: < 5.1.12; UDM-SE: < 5.1.12; UDM-Pro-Max: < 5.1.12; UDM-Beast: < 5.1.11; EFG: < 5.1.12; UDW: < 5.1.12; UDR: < 5.1.12; UDR7: < 5.1.12; UDR-5G: < 5.1.12; Express 7: < 5.1.12; UNVR: < 5.1.12; UNVR-Pro: < 5.1.12; UNVR-Instant: < 5.1.12; UNVR-G2: < 5.1.12; UNVR-G2-Pro: < 5.1.12; ENVR: < 5.1.12; ENVR-Core: < 5.1.12; UNAS-2: < 5.1.10; UNAS-4: < 5.1.10; UNAS-Pro: < 5.1.10; UNAS-Pro-4: < 5.1.10; UNAS-Pro-8: < 5.1.10; UCKP: < 5.1.12; UCK: < 5.1.12; UCK-Enterprise: < 5.1.12; UCG-Ultra: < 5.1.12; UCG-Max: < 5.1.12; UCG-Fiber: < 5.1.12; UCG-Industrial: < 5.1.12 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-31382↗CISA KEV record↗CVE authority or vendor reference↗Public exploit reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-34910 · cve.blacktree.nl