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 0.45% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-84750High confidence
Ultimate Addons for Contact Form 7 3.2.4 - 3.5.50 - Unauthenticated Arbitrary File Upload via Signature Field
Unknown · Ultra Addons for Contact Form 7
6.5MediumCVSS 3.1
Scheduled
Fix not verifiedMedium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityMedium→Operational priority:Medium, unchanged from published severity.unchanged
Compensating controls
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Unknown Ultra Addons for Contact Form 7 and falls inside the recorded affected range.
- Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Fix not verified01
What, why and how
The Ultra Addons for Contact Form 7 WordPress plugin before 3.5.51 does not validate the type or extension of files uploaded through one of its form fields, and stores them at a predictable public path with the attacker-chosen extension intact, allowing unauthenticated users to upload arbitrary files. The PHP handler shipped by default with the Debian and Ubuntu Apache packages maps .phar to PHP alongside .php and .phtml, so on that stack the uploaded file is executed and the issue leads to Remote Code Execution and full site takeover. Where the host routes only .php to the PHP handler, the same file is instead served from the site's own origin with its script intact, leading to Stored Cross-Site Scripting.
What
The Ultra Addons for Contact Form 7 WordPress plugin before 3.5.51 does not validate the type or extension of files uploaded through one of its form fields, and stores them at a predictable public path with the attacker-chosen extension intact, allowing unauthenticated users to upload arbitrary files. The PHP handler shipped by default with the Debian and Ubuntu Apache packages maps .phar to PHP alongside .php and .phtml, so on that stack the uploaded file is executed and the issue leads to Remote Code Execution and full site takeover. Where the host routes only .php to the PHP handler, the same file is instead served from the site's own origin with its script intact, leading to Stored Cross-Site Scripting.
Why
The upload path does not sufficiently restrict the type, name, location or later execution of attacker-supplied files.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.
What
The Ultra Addons for Contact Form 7 WordPress plugin before 3.5.51 does not validate the type or extension of files uploaded through one of its form fields, and stores them at a predictable public path with the attacker-chosen extension intact, allowing unauthenticated users to upload arbitrary files. The PHP handler shipped by default with the Debian and Ubuntu Apache packages maps .phar to PHP alongside .php and .phtml, so on that stack the uploaded file is executed and the issue leads to Remote Code Execution and full site takeover. Where the host routes only .php to the PHP handler, the same file is instead served from the site's own origin with its script intact, leading to Stored Cross-Site Scripting.
Why
The upload path does not sufficiently restrict the type, name, location or later execution of attacker-supplied files.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 → Unrestricted Upload of File with Dangerous Type → execute code or commands in the affected security context
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-434 ↗
CWE-434: Unrestricted Upload of File with Dangerous Type. The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
- 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:U/C:L/I:L/A:NCommon 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.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.- Post-exploitation / living off the land
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
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. - Fix not verified
- Affected
- Ultra Addons for Contact Form 7: 3.2.4 < 3.5.51
- Fixed
- No fixed version is explicitly recorded in the structured CVE data.
- Action
- No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
- 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 19 Sept 2026 · Last source change 19 Sept 2026, 13:09 UTC · CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source FIRST · tracked since 2026-09-19
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-83502
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled
Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
- ENISA EUVD mappingEUVD-2026-83502 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-83502"}
- SeveritySeverity changed from Unknown to Medium.CISA ADP ↗
- Before
- Unknown
- After
- Medium
- CVSS scoreCVSS score changed from not recorded to 6.5 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N).CISA ADP ↗
- Before
- not recorded
- After
- 6.5 (CVSS 3.1 · CISA ADP · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
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.