Skip to main content

Upcasted S3 Offload CVE-2026-62035

| EUVDEUVD-2026-96470 MEDIUM
Missing Authorization (CWE-862)
2026-10-10 Patchstack GHSA-5g33-v9wf-46c9
6.3
CVSS 3.1 · Vendor: Patchstack
View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Register/obtain subscriber account
  2. Delivery
    Authenticate to WordPress
  3. Exploit
    Invoke unprotected plugin S3 endpoint
  4. Execution
    Perform unauthorized S3/data action
  5. Impact
    Limited data disclosure or modification

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires a valid authenticated WordPress account at Subscriber (low-privilege) level, per CVSS PR:L and the 'Subscriber Broken Access Control' description - this is the primary limiting factor, making open/self-service user registration on the target site the key enabling condition. The affected plugin is 'AWS S3 for WordPress Plugin - Upcasted' at version 3.1.0 or earlier. No user interaction is needed (UI:N) and the attack is network-reachable (AV:N). Exploitation is bounded to the limited actions the missing authorization check exposes (low C/I/A impact), not full administrative control; sites that disable public registration or restrict subscriber creation substantially reduce exposure.

Impact

This is a moderate-severity (CVSS 6.3) missing-authorization flaw (CWE-862) in the 'AWS S3 for WordPress Plugin - Upcasted' (versions ≤ 3.1.0). The CVSS vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L indicates network-reachable, low-complexity exploitation that requires low privileges (PR:L) - consistent with the description's 'Subscriber' broken access control, meaning any low-privilege authenticated WordPress account suffices. Impact is uniformly low across confidentiality, integrity, and availability, so this is a scope-limited authorization gap rather than a full takeover. No EPSS score was provided, there is no CISA KEV listing, and no public exploit code was supplied in the intelligence, so exploitation status is 'no public exploit identified at time of analysis.' The signals are internally consistent (authenticated low-privilege network attack with limited impact), so this reads as a genuine but not urgent issue: real priority is driven mainly by the low bar of needing only a subscriber account on sites that allow open registration, not by any evidence of active or automated exploitation. Note: the source is a single Patchstack advisory; no independent NVD CVSS or vendor confirmation of the patched version was provided, so the score and affected-version ceiling rely on that one source.

Exploit ScenarioDerived

On a WordPress site running this plugin where self-registration is enabled, an attacker registers an ordinary subscriber account, authenticates, and invokes a plugin action or endpoint that fails to enforce a proper capability check. This lets the subscriber perform S3-offload operations or read/alter data they should not have access to, yielding limited confidentiality and integrity impact. No public proof-of-concept was provided, and the attack requires a valid (if low-privilege) account.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.2% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAIv1 – Oct 10, 2026

Missing authorization checks in the Upcasted S3 Offload plugin (published as 'AWS S3 for WordPress Plugin - Upcasted') through version 3.1.0 let any authenticated user holding only the Subscriber role invoke plugin functionality that should be reserved for higher-privileged accounts, yielding limited confidentiality, integrity, and availability impact rather than full site takeover. The attack is network-reachable and requires no user interaction, but the PR:L rating means an attacker must first possess a valid low-privilege WordPress account - most commonly obtained through open or self-service user registration - which is the principal limiting factor on real-world exposure. There is no public exploit code identified at time of analysis and no indication of active exploitation, and the moderate CVSS score of 6.3 reflects the constrained, low-impact actions that the missing check exposes.

RemediationAI

Patch status is not confirmed in the available data: the advisory references do not specify a fixed plugin version, so the primary action is to monitor the Patchstack advisory and the vendor's release notes at https://patchstack.com/database/wordpress/plugin/upcasted-s3-offload/ and update to the first plugin release above 3.1.0 as soon as it is published. In the interim, the most effective compensating control is to eliminate the prerequisite privilege: disable public/self-service user registration (Settings > General > Membership in WordPress) and remove or review any existing Subscriber and other low-privilege accounts, with the trade-off that legitimate community sign-ups are blocked and existing subscriber accounts must be audited or removed. If the plugin's S3 offloading is not essential, deactivate and remove it entirely - the trade-off is loss of media offload/CDN functionality and possible broken media URLs until a replacement is configured. Administrators can also restrict access to wp-admin and admin-ajax.php by IP or authentication layer and deploy WAF/virtual-patching rules (for example, Patchstack's vPatch protection, since this vulnerability was reported through Patchstack) to block Subscriber-level requests to the vulnerable plugin endpoints, though virtual patching can cause false positives on legitimate traffic and is a stopgap rather than a fix. Finally, review plugin-side and web server logs for Subscriber-role requests to the plugin's AJAX/REST handlers and treat any such activity as attempted exploitation.

Affected VersionsENISA

AWS S3 for WordPress Plugin – Upcasted n/a ≤3.1.0

Affected Packages

euvd aws_s3_for_wordpress_plugin_upcasted no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause class is CWE-862 (Missing Authorization). The plugin registers server-side handlers (typically WordPress admin-ajax actions, admin-post handlers, or REST routes) that perform privileged S3-related operations but fail to enforce a proper capability check such as current_user_can() before executing them. WordPress ships a role hierarchy in which Subscriber is the lowest authenticated role, normally holding only read-level capabilities; because the plugin does not verify that the caller holds an administrative or editor-level capability, a Subscriber can reach code paths intended for site administrators. The CVSS:3.1 vector AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L confirms this profile: reachable over the network with low attack complexity, requiring only low privileges, needing no victim interaction, scoped to the plugin, and producing only low-level impact across all three security properties - consistent with the missing check exposing a narrow set of actions rather than administrative control. The affected component is tracked by the CPE cpe:2.3:a:upcasted:aws_s3_for_wordpress_plugin_-_upcasted:*:*:*:*:*:*:*:*, and the issue was reported through the Patchstack disclosure channel; no EPSS score or CISA KEV entry is present in the available intelligence.

Know when Wordpress Plugin gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Severity by source

Vendor (Patchstack) PRIMARY 6.3 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
vuln.today AI 6.3 MEDIUM

Network-reachable missing authorization exploitable by any authenticated subscriber (PR:L), no user interaction, with limited confidentiality, integrity, and availability impact confined to the vulnerable site (S:U).

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

Primary rating from Vendor (Patchstack).

CVSS VectorVendor: Patchstack

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

DescriptionCVE.org

Subscriber Broken Access Control in AWS S3 for WordPress Plugin - Upcasted <= 3.1.0 versions.

Threat Intelligence Overview

EPSS Score
0.2%
Top 85% exploitable
Prevalence
Low
niche third-party WordPress S3-offload plugin, small install base
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

CVE-2023-6553 CRITICAL POC
9.8 Dec 15

The Backup Migration plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 1

CVE-2024-5084 CRITICAL POC
9.8 May 23

The Hash Form - Drag & Drop Form Builder plugin for WordPress is vulnerable to arbitrary file uploads due to missing fil

CVE-2024-44000 CRITICAL POC
9.8 Oct 20

Authentication bypass in the LiteSpeed Cache WordPress plugin (versions prior to 6.5.0.1) allows unauthenticated remote

CVE-2020-36847 CRITICAL POC
9.8 Jul 12

The Simple File List plugin for WordPress through version 4.2.2 contains an unauthenticated remote code execution vulner

CVE-2025-27007 CRITICAL POC
9.8 May 01

The SureTriggers WordPress plugin through version 1.0.82 contains a privilege escalation vulnerability that allows unaut

CVE-2016-1209 CRITICAL POC
9.8 May 14

The Ninja Forms plugin before 2.9.42.1 for WordPress allows remote attackers to conduct PHP object injection attacks via

CVE-2024-4443 CRITICAL POC
9.8 May 22

The Business Directory Plugin - Easy Listing Directories for WordPress plugin for WordPress is vulnerable to time-based

CVE-2024-1698 CRITICAL POC
9.8 Feb 27

SQL injection in the NotificationX WordPress plugin (versions up to and including 2.8.2) allows unauthenticated remote a

CVE-2023-6875 CRITICAL POC
9.8 Jan 11

The POST SMTP Mailer - Email log, Delivery Failure Notifications and Best Mail SMTP for WordPress plugin for WordPress i

CVE-2024-1512 CRITICAL POC
9.8 Feb 17

The MasterStudy LMS WordPress Plugin - for Online Courses and Education plugin for WordPress is vulnerable to union base

CVE-2024-4295 CRITICAL POC
9.8 Jun 05

The Email Subscribers by Icegram Express plugin for WordPress is vulnerable to SQL Injection via the ‘hash’ parameter in

CVE-2024-50498 CRITICAL POC
10.0 Oct 28

Remote code execution in the WP Query Console WordPress plugin (versions up to and including 1.0) by Ajit Bohra allows u

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy