CVE-2026-42698

Executive Summary

CVE-2026-42698 is a race condition vulnerability (CWE-362) affecting the Themeum Tutor LMS WordPress plugin through version 4.1.1. Concurrent execution using a shared resource with improper synchronization allows an authenticated attacker with low privileges to manipulate shared state, resulting in a high-integrity impact. No public exploit, Nuclei template, or patch is currently available, and the vulnerability has not been added to CISA KEV.

Technical Analysis

The vulnerability is classified under CWE-362, "Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')." As described by NVD, the flaw allows "Leveraging Race Conditions" within the Tutor LMS plugin, affecting versions from n/a through 4.1.1.

A race condition arises when two or more execution contexts access a shared resource without adequate locking, ordering, or atomicity guarantees. The result is a time-of-check-to-time-of-use (TOCTOU) gap or an interleaving of operations that produces an unintended state. In the context of a WordPress plugin such as Tutor LMS, shared resources classically include database rows (enrollment records, quiz attempts, progress tracking, order or transaction records), transient/option values, file handles, or in-memory request-scoped state. Because the NVD description does not disclose the specific function, endpoint, table, or parameter involved, the exact shared resource and the precise sequence of operations cannot be determined from the available intelligence. What is derivable from the scoring metadata is the following:

• The attack vector is Network (AV:N), meaning the vulnerable code path is reachable remotely, consistent with a web-facing WordPress plugin.
• Attack complexity is High (AC:H), which is typical for race conditions: successful exploitation depends on precise timing and the attacker's ability to win a narrow concurrency window, often requiring many parallel requests.
• Privileges Required is Low (PR:L), indicating the attacker must hold at least a basic authenticated role (for example, a subscriber or student-level account) rather than exploiting anonymously.
• User Interaction is None (UI:N), so no victim action is needed beyond the attacker sending requests.
• Scope is Unchanged (S:U), meaning the vulnerable component and impacted component are the same security authority.
• Confidentiality impact is None (C:N), Integrity impact is High (I:H), and Availability impact is None (A:N). This profile indicates that exploitation corrupts or alters data or state rather than disclosing secrets or causing denial of service.

The combination of PR:L, AC:H, high integrity impact, and no confidentiality/availability impact is characteristic of a logic-flaw race condition where an authenticated user can cause unintended state transitions in application data — for example, duplicating or altering a record whose integrity is expected to be protected by synchronization. The specific business object affected (enrollment, payment, grading, content access, or similar) is not specified in the available description and should not be assumed.

Because there is no vendor confirmation of a root cause, no CVE analysis (CNA) description text, and no patch diff, the precise code-level mechanism — such as an unsynchronized database write, a non-atomic read-modify-write, or a missing lock around a shared file — remains unconfirmed. Analysts should treat the vulnerable code path as unknown pending vendor disclosure and should prioritize behavior-based detection over signature-based detection.

Exploitation Scenarios

No public proof-of-concept, Nuclei template, or exploit code is available for CVE-2026-42698. The attack chain below is inferred strictly from the vulnerability class (CWE-362) and the CVSS metadata; it does not rely on any unpublished implementation detail, function name, endpoint, or parameter.

1. Reconnaissance / target identification

   • Identify internet-facing WordPress installations running Tutor LMS by fingerprinting plugin assets and LMS-specific markers. Shodan dorks in this report (for example http.html:"wp-content/plugins/tutor") support large-scale identification.
   • Enumerate plugin version to determine whether the target is at or below 4.1.1.
   • Obtain or register a low-privileged account, satisfying the PR:L requirement (student/subscriber-level access is theoretically sufficient since no elevated privileges are scored).

2. Triggering the race condition

   • The attacker issues multiple concurrent requests against the application function that performs an unsynchronized read-modify-write or check-then-act sequence on a shared resource.
   • Because AC:H, the attacker must fire requests in tight parallel windows (using concurrent HTTP clients or request racing) and repeat attempts to win the timing window.
   • Success is achieved when interleaving causes an unintended state transition — e.g., a duplicate operation that should be idempotent, an altered record, or a bypass of a logical constraint. The precise resource and operation cannot be enumerated from available data.

3. Execution method at the vulnerability-class level

   • The "payload" is not a memory-corruption or injection string but a stream of synchronized concurrent requests that exploit missing locking/atomicity.
   • No authentication bypass, file write, or remote code execution is indicated by the CVE data; exploitation is a logic/integrity attack.

4. Post-exploitation impact

   • Per the CVSS vector, the attacker can achieve a High Integrity impact on data or state while confidentiality and availability remain unaffected and scope is unchanged.
   • Depending on the business object (not disclosed), consequences could include corrupted enrollment, progress, grading, or transactional records. These are potential outcomes of the vulnerability class, not confirmed specifics for this CVE.

No exploit-in-the-wild evidence, threat actor attribution, or campaign data is available for CVE-2026-42698.

Impact Assessment

• CVSS 3.1 base score: 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N.
• Exploitability subscore is moderated by High attack complexity (AC:H) and the Low privileges requirement (PR:L); the Network attack vector keeps remote exploitation feasible for authenticated users.
• Impact subscore: Integrity is the only impacted metric (I:H). Confidentiality (C:N) and Availability (A:N) are scored as no impact, and Scope is Unchanged (S:U).
• Affected systems: WordPress installations running the Tutor LMS plugin at versions through 4.1.1.
• Blast radius: limited to the integrity of application-managed data/state within the affected plugin. No data disclosure or service disruption is scored.
• Business risk is highest for learning platforms whose enrollment, assessment, or transactional records must be trustworthy; undetected integrity manipulation can compromise the validity of academic or business data.
• EPSS: Not yet scored by FIRST.org. Do not assume an exploitation probability.
• CISA KEV: Not listed. No known active exploitation reported in the provided data.

Detection Guidance

Note: No public PoC exists. Detection content below is behavior-oriented and targets the vulnerability class; rules should be tuned to baseline environment traffic to reduce false positives.

Sigma Rule

title: Potential Race Condition Exploitation Against Tutor LMS (CVE-2026-42698)
id: 5c1f9a2e-7b3d-4e11-9a2c-8f0d1b6e4a77
status: experimental
description: Detects bursts of concurrent authenticated requests to Tutor LMS endpoints consistent with race condition triggering attempts.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-42698
author: valtersit.com
date: 2026-01-01
tags:
  - attack.t1190
  - cve.2026-42698
logsource:
  category: webserver
  product: apache
detection:
  selection_plugin:
    cs-uri-stem|contains:
      - '/wp-content/plugins/tutor'
      - '/wp-json/tutor'
  selection_method:
    cs-method: 'POST'
  timeframe: 5s
  condition: selection_plugin and selection_method | count() by c-ip > 15
falsepositives:
  - Legitimate high-volume LMS activity
  - Load testing
level: medium

YARA Rule

rule CVE_2026_42698_TutorLMS_RaceCondition_Indicator
{
    meta:
        description = "Heuristic indicator for Tutor LMS plugin artifacts referencing CVE-2026-42698 affected versions (<= 4.1.1). Detection only; not a proof of exploitation."
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-42698"
        date = "2026-01-01"
        severity = "medium"

    strings:
        $plugin_header = "Plugin Name: Tutor LMS" ascii wide nocase
        $version_marker = "Tutor LMS" ascii wide nocase
        $wp_plugin_path = "wp-content/plugins/tutor" ascii wide nocase

    condition:
        uint16(0) == 0x3C3F or any of ($plugin_header, $version_marker) or $wp_plugin_path
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-42698 Possible Tutor LMS Race Condition Exploitation Attempt"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/wp-content/plugins/tutor"; reference:cve,2026-42698; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-42698; threshold:type both, track by_src, count 15, seconds 5; classtype:attempted-user; sid:202642698; rev:1;)

Note: Because the exact request URI for the vulnerable endpoint is not disclosed, the rule keys on the plugin URI namespace with a rate-based threshold. Tune the count/seconds window to your environment.

Elastic Detection

sequence by source.ip with maxspan=3s
  [ network where http.request.method == "POST" and
      http.request.uri : "/wp-content/plugins/tutor*" ]
  [ network where http.request.method == "POST" and
      http.request.uri : "/wp-content/plugins/tutor*" ]
  [ network where http.request.method == "POST" and
      http.request.uri : "/wp-content/plugins/tutor*" ]

This EQL sequence flags rapid successive POSTs to Tutor LMS paths, a behavioral proxy for race condition attempts. Adjust the number of events and maxspan to balance sensitivity.

Splunk SPL Query

index=web sourcetype=access_combined
| where match(uri, "(?i)/wp-content/plugins/tutor|/wp-json/tutor")
| where method="POST"
| bin _time span=5s
| stats count as req_count, dc(uri) as distinct_uris by src_ip, _time
| where req_count > 15
| sort - req_count
| table _time src_ip req_count distinct_uris

This identifies source IPs generating high-volume concurrent POST traffic to Tutor LMS endpoints within short windows.

Wazuh OSSEC Rule

<group name="web,wordpress,tutor_lms,">
  <rule id="100426" level="7">
    <if_sid>31100</if_sid>
    <match>/wp-content/plugins/tutor</match>
    <description>Tutor LMS access detected (CVE-2026-42698 monitoring)</description>
    <options>no_full_log</options>
  </rule>

  <rule id="100427" level="10" frequency="15" timeframe="5">
    <if_matched_sid>100426</if_matched_sid>
    <same_source_ip />
    <description>Possible race condition exploitation against Tutor LMS (CVE-2026-42698): excessive concurrent requests from same source</description>
    <mitre>
      <id>T1190</id>
    </mitre>
  </rule>
</group>

The correlated rule uses Wazuh's frequency/timeframe matching to detect request bursts from a single source IP against the Tutor LMS path namespace.

Mitigation & Patch Guidance

Patch confidence: 0/4 — UNPATCHED. No patch evidence from any tracked source, no vendor fix, and no workaround are available as of this report. There is no confirmed fixed version for CVE-2026-42698.

1. Immediate mitigations

   • Implement rate limiting and concurrency controls on Tutor LMS endpoints, particularly endpoints that create or modify records, to reduce the feasibility of winning the race condition window (AC:H means the attacker needs repeated parallel attempts).
   • Enforce least privilege: limit which accounts can reach state-modifying LMS functionality, since exploitation requires Low privileges (PR:L).
   • Deploy WAF/edge rules that throttle or challenge single-source request bursts to plugin paths.
   • Add integrity monitoring/auditing on LMS records (enrollment, progress, grading, transactional data) to detect unauthorized state changes; the scored impact is Integrity-only.
   • Monitor vendor channels and the NVD entry for a fixed version; do not assume a version above 4.1.1 is fixed until confirmed.

2. Patch/upgrade steps

   • No patch is available. Track Themeum's advisories and the NVD record for CVE-2026-42698.
   • When a fixed release is published, test in staging and upgrade promptly. Until then, treat all versions through 4.1.1 as affected and maintain compensating controls.

3. Long-term hardening

   • Apply server-side synchronization (transactions, atomic operations, row-level locking, or idempotency keys) as a vendor-side requirement; as a customer, press the vendor for a root-cause fix rather than a rate-limit workaround.
   • Reduce plugin attack surface and remove unused LMS components.
   • Maintain logging of authenticated state-changing requests for forensic and detection use, and integrate with SIEM correlation for concurrency bursts.
   • Include third-party WordPress plugin components in routine vulnerability management and SBOM tracking.

No workaround is documented by the vendor or the CNA.

References

• NVD — CVE-2026-42698: https://nvd.nist.gov/vuln/detail/CVE-2026-42698
• CWE-362, Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'): https://cwe.mitre.org/data/definitions/362.html
• FIRST EPSS (not yet scored for this CVE): https://www.first.org/epss/
• CISA Known Exploited Vulnerabilities Catalog (CVE-2026-42698 not listed): https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• Themeum Tutor LMS product page (vendor channel for future advisories; no CVE-specific advisory available at time of writing): https://tutorlms.com/

Threat actor campaigns: none identified. No exploit-in-the-wild evidence, PoC, or Nuclei template is available for CVE-2026-42698.