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Full vulnerability report · 2026
CVE-2026-46376High confidence

FreePBX: Unauthenticated Use of Hard-Coded Credentials Vulnerability in FreePBX UCP Interface

FreePBX · security-reporting

Official source article: GitHub GHSA-M55X-H47X-V3GX ↗. Check the applicable product and release in the original source.

9.3CriticalCVSS 4.0
Recommended action
Within 72 hours

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.

Mitigation available
R
Operational reassessment

Published severity in operational context

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

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.50% for the current model date.

Compensating controls

  • Apply the linked authoritative mitigation while planning the permanent fix.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs FreePBX security-reporting and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  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-2026-33295

No EUVD known-exploited evidence

FreePBX is an open source IP PBX. From 15.0.42 to before 16.0.45 and 17.0.7, unauthenticated users may be able to access the User Control Panel (UCP) using hard-coded initial template credentials if these were not immediately changed by the Administrator who enabled UCP. Authenticated access to ACP is required for the initial setup of UCP generic templates, but after that, without further steps by the admin, unauthenticated users may be able to gain access. This vulnerability is fixed in 16.0.45 and 17.0.7.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
9.3 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 72 hours

Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.

Mitigation available
01

What, why and how

FreePBX is an open source IP PBX. From 15.0.42 to before 16.0.45 and 17.0.7, unauthenticated users may be able to access the User Control Panel (UCP) using hard-coded initial template credentials if these were not immediately changed by the Administrator who enabled UCP. Authenticated access to ACP is required for the initial setup of UCP generic templates, but after that, without further steps by the admin, unauthenticated users may be able to gain access. This vulnerability is fixed in 16.0.45 and 17.0.7.

What

FreePBX is an open source IP PBX. From 15.0.42 to before 16.0.45 and 17.0.7, unauthenticated users may be able to access the User Control Panel (UCP) using hard-coded initial template credentials if these were not immediately changed by the Administrator who enabled UCP. Authenticated access to ACP is required for the initial setup of UCP generic templates, but after that, without further steps by the admin, unauthenticated users may be able to gain access. This vulnerability is fixed in 16.0.45 and 17.0.7.

Why

A credential embedded in the product can be recovered or reused across installations instead of being unique to one deployment.

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

FreePBX is an open source IP PBX. From 15.0.42 to before 16.0.45 and 17.0.7, unauthenticated users may be able to access the User Control Panel (UCP) using hard-coded initial template credentials if these were not immediately changed by the Administrator who enabled UCP. Authenticated access to ACP is required for the initial setup of UCP generic templates, but after that, without further steps by the admin, unauthenticated users may be able to gain access. This vulnerability is fixed in 16.0.45 and 17.0.7.

Why

A credential embedded in the product can be recovered or reused across installations instead of being unique to one deployment.

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.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Use of Hard-coded Credentials → 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
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-798 ↗

CWE-798: Use of Hard-coded Credentials. The product contains hard-coded credentials, such as a password or cryptographic key.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: 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.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
NetworkUnauthenticatedCWE-798
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-33295Official EUVD mapping

FreePBX is an open source IP PBX. From 15.0.42 to before 16.0.45 and 17.0.7, unauthenticated users may be able to access the User Control Panel (UCP) using hard-coded initial template credentials if these were not immediately changed by the Administrator who enabled UCP. Authenticated access to ACP is required for the initial setup of UCP generic templates, but after that, without further steps by the admin, unauthenticated users may be able to gain access. This vulnerability is fixed in 16.0.45 and 17.0.7.

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260603Security Bulletin 3 Jun 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 3 Jun 2026, published on 3 June 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-017778Sangomaのfreepbxにおけるハードコードされた認証情報の使用に関する脆弱性

FreePBXはオープンソースのIP PBXです。バージョン15.0.42から16.0.45未満および17.0.7までの間において、管理者がUCPを有効化した際に初期のテンプレート資格情報を直ちに変更しなかった場合、認証されていないユーザーがハードコードされた初期テンプレートの資格情報を使用してユーザーコントロールパネル（UCP）にアクセスできる可能性があります。UCP一般テンプレートの初期設定にはACPへの認証済みアクセスが必要です。しかし、その後管理者が追加の対策を講じない場合、認証されていないユーザーがアクセスを得る可能性があります。この脆弱性は16.0.45および17.0.7で修正されています。

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.
Mitigation available
Affected
security-reporting: >= 15.0.42, < 16.0.45, >= 17.0.1, < 17.0.7
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Apply the mitigation in the linked authoritative guidance while planning the vendor's permanent fix.
Workaround
A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
04

Evidence and provenance

Published 29 May 2026 · Last source change 28 Sept 2026, 16:57 UTC · CWE-798 · Use of Hard-coded Credentials

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-2026-33295
Product sourceCNA
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. Affected versionsThe structured affected or fixed version information changed.
    Before
    >= 15.0.42, < 16.0.45; >= 17.0.1, < 17.0.7 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    security-reporting: >= 15.0.42, < 16.0.45, >= 17.0.1, < 17.0.7 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Mitigation reference recorded
ENISA EUVD · EUVD-2026-33295↗CVE authority or vendor reference · GitHub GHSA-M55X-H47X-V3GX↗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-2026-46376 · cve.blacktree.nl