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CVE-2026-8181: Burst Statistics Authentication Bypass

CVSS · Critical
9.8
In CISA KEV
No
Published
Nov 12
Patch SLA & TriageVector: Network
24 to 48 hours

Critical CVSS (9.8) reachable over network.

Exposure:
Control:
CVSS v3.1 Blast RadiusCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Decode Vector & Sub-Scores →
CVE explainers 10 min read
Security Research Desk Source-checked
Auto-checked against the official CVE record · Human-reviewed after publishing · Updated 2026-11-12
Threat Intelligence
2News mentions
1GitHub refs
99.0%EPSS score
▲ Escalation ViewOne CVE, briefed at three altitudes — skim the Brief, weigh the Impact, or work the Runbook. The way a SOC actually reads it.
CISOBrief · 30-second brief

TL;DR - CVE-2026-8181 is a CVSS 9.8 authentication bypass in Burst Statistics for WordPress. - Versions 3.4.0 through 3.4.1.1 are affected. Upgrade to 3.4.2 or later. - Exploitation has been reported, although the CVE is not currently listed in CISA KEV. - If you cannot upgrade immediately, disable or remove the plugin and investigate the site for compromise.

CVE-2026-8181 is a critical Burst Statistics vulnerability that can let an unauthenticated attacker impersonate a WordPress administrator when the attacker knows a valid administrator username. The issue affects the Burst Statistics – Privacy-Friendly WordPress Analytics plugin versions 3.4.0 through 3.4.1.1.

Sites running an affected version should be treated as exposed until the plugin is upgraded, disabled, or removed. Organizations should also review administrator activity and site integrity because exploitation has been reported.

Vulnerability Summary

The vulnerability affects the plugin’s MainWP proxy authentication path. An attacker can submit a crafted Basic Authentication request containing a known WordPress administrator username and an arbitrary password. Because of an error in the authentication logic, the request may be accepted as an administrator request.

The attacker does not need a valid WordPress password, an existing account, or victim interaction. Successful exploitation can enable privileged actions, including changes that may lead to complete site takeover.

Field Detail
CVE ID CVE-2026-8181
CVSS v3.1 9.8 Critical
CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector Network
Authentication or privileges required None
Affected product Burst Statistics – Privacy-Friendly WordPress Analytics
Affected versions 3.4.0 through 3.4.1.1
Fixed version 3.4.2
Patch available Yes
CISA KEV status Not listed as of the supplied research data
Exploitation status Reported exploitation in the wild

The combination of remote reachability, no required privileges, and high impact across confidentiality, integrity, and availability makes this an urgent patching issue.

Analyst’s Take: Upgrade or disable the plugin first. The absence of a CISA KEV listing does not mean affected sites are safe, particularly because exploitation has been reported.

AnalystImpact · assess the risk

Root Cause

The flaw is in the plugin’s MainWP proxy authentication logic, specifically the is_mainwp_authenticated() function in:

includes/Frontend/class-mainwp-proxy.php

The function processes application-password validation supplied through the HTTP Authorization header but incorrectly handles the associated return value. As a result, the authentication check can accept a random Basic Authentication password when the supplied username belongs to a WordPress administrator.

In practical terms, the password is not properly enforced as a valid credential in the affected code path. The issue is classified as CWE-287: Improper Authentication.

This is an authentication bypass rather than a conventional authorization flaw. An attacker does not first authenticate as a lower-privileged user and then escalate permissions. Instead, the vulnerable request can cause WordPress to treat the attacker as an administrator during request processing.

Public source references expose the affected MainWP proxy logic, but the available research does not establish a vendor-published technical patch commit. Defenders should rely on the reported fixed release, 3.4.2, rather than attempting to reconstruct or locally modify the authentication code.

Who Needs to Act

Organizations running Burst Statistics versions 3.4.0, 3.4.1, or 3.4.1.1 need to act. The affected maintainer is identified as burstbv, and the product is distributed as a WordPress plugin.

Product Affected range Fixed release Required action
Burst Statistics – Privacy-Friendly WordPress Analytics 3.4.0–3.4.1.1 3.4.2 Upgrade immediately or disable/remove the plugin

Upgrade to version 3.4.2 or later, subject to normal compatibility testing. If the plugin cannot be upgraded promptly, disabling or removing it is safer than leaving the affected authentication path available.

Do not assume that a site is safe because the MainWP integration is not actively used. Exposure depends on how the plugin handles incoming requests, not only on whether an administrator has configured a particular workflow.

Review every WordPress installation managed by the organization, including:

  • Production sites.
  • Staging and development sites.
  • Multisite networks.
  • Sites outside centralized plugin management.
  • Internet-facing hosts used for testing or temporary deployments.

A vulnerable staging or development site can still expose credentials, configuration data, or a foothold for further attacks.

For broader WordPress hardening, review the guidance in our WordPress security resources and ensure that plugin inventory and administrative access are centrally monitored.

CVSS 9.8 Severity Explained

The CVSS v3.1 score is 9.8 Critical:

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

The score is high because the attack:

  • Is remotely reachable over the network (AV:N).
  • Requires no unusual conditions (AC:L).
  • Requires no existing account or privileges (PR:N).
  • Requires no victim interaction (UI:N).

These characteristics make exploitation practical against exposed WordPress sites, particularly where administrator usernames can be discovered through public content, author archives, login behavior, or other site-specific information.

The impact metrics are also high:

  • Confidentiality (C:H): Administrative access can expose site data, configuration, credentials, and integrations.
  • Integrity (I:H): An impersonated administrator may alter content, users, plugins, themes, settings, and scheduled tasks.
  • Availability (A:H): The attacker may disrupt the site, remove functionality, or modify deployment settings.

The scope is unchanged (S:U), meaning the assessed impact remains within the vulnerable WordPress security authority. That does not make the operational consequences minor: administrative control of a WordPress site can affect public content, customer data, credentials, integrations, and site visitors.

Exploitation Status

Available security reporting describes exploitation in the wild. Bitdefender reported active exploitation and cited Wordfence telemetry involving thousands of blocked attacks.

The CVE is not currently listed in the CISA Known Exploited Vulnerabilities catalog based on the supplied research. There is therefore no CISA KEV date-added field, due date, required action, or KEV ransomware-campaign designation to report.

Absence from KEV does not prove that exploitation has not occurred. It only means that the vulnerability does not currently have a CISA KEV listing.

A separate, verified public exploit repository was not identified in the retrieved sources. Available references reveal the vulnerable authentication logic and provide enough information to understand the flaw, but the research does not confirm a standalone weaponized proof-of-concept repository. The lack of a confirmed public repository should not delay remediation.

ResponderRunbook · act now

Detection Guidance

Start with asset inventory. Identify every WordPress site running Burst Statistics and determine the installed plugin version.

With WP-CLI, check the installed version:

wp plugin get burst-statistics --field=version

For multisite deployments, enumerate sites and plugin status through the organization’s normal WordPress management tooling. Where WP-CLI is unavailable, inspect the plugin metadata file, typically:

wp-content/plugins/burst-statistics/burst-statistics.php

Detection is complicated because the vulnerability involves HTTP Basic Authentication and request-time impersonation. Web-server logs may record the request path and status code but generally will not log the decoded Authorization credential.

Do not log raw Authorization headers for troubleshooting or detection. They contain sensitive credentials.

Look for suspicious requests to MainWP-related or plugin-related paths, particularly requests that contain a Basic Authentication header and are followed by administrator-level activity. If reverse proxies record request-header presence, a generic search may help identify candidates:

zgrep -Ei \
  'authorization: *Basic|mainwp|burst-statistics|class-mainwp-proxy' \
  /var/log/nginx/access.log* /var/log/apache2/access.log*

Header logging varies by deployment, so this query may not return useful results everywhere. A more reliable approach is to correlate web requests with WordPress and application logs.

Investigate administrative actions occurring immediately after unusual unauthenticated requests, including:

  • New administrator accounts or unexpected role changes.
  • Plugin or theme installation, activation, modification, or deletion.
  • Changes to wp-config.php, site URLs, users, scheduled tasks, or security settings.
  • Unexpected REST, AJAX, XML-RPC, or MainWP-related requests.
  • Administrative actions from unfamiliar IP addresses or user agents.
  • New PHP files in wp-content/uploads, plugin directories, or theme directories.

If a web application firewall or reverse proxy captures request metadata, create a temporary detection rule for Basic Authentication requests directed at the affected site. Alert on successful responses and subsequent privileged activity.

Avoid relying on one path signature. Endpoint routing and logging formats vary between WordPress deployments.

Technical Detection Notes

A practical SIEM query can correlate Basic Authentication indicators with successful responses and subsequent WordPress administrative events:

http.request.headers.authorization exists
AND (url.path contains "mainwp" OR url.path contains "burst")
AND http.response.status_code in (200, 201, 204, 302)

This is a starting pattern, not a universal signature. Validate it against normal site traffic and add detections for:

  • Administrator creation.
  • Plugin changes.
  • Theme changes.
  • Application-password changes.
  • Unexpected scheduled tasks.
  • Login or session activity from unfamiliar locations.

Do not treat every Basic Authentication request as malicious, but prioritize requests associated with Burst Statistics, unfamiliar source addresses, unusual user agents, or unexpected privileged changes.

Remediation and Patching

Upgrade Burst Statistics to 3.4.2 or later.

With WP-CLI:

wp plugin update burst-statistics

Confirm the installed version:

wp plugin get burst-statistics --field=version

If the site is managed through the WordPress administrative interface, update Burst Statistics from the Plugins page and verify that the displayed version is 3.4.2 or later.

For fleets, use the organization’s approved WordPress management platform or deployment pipeline. Record the resulting version for every site.

If immediate upgrading is not possible, disable the plugin:

wp plugin deactivate burst-statistics

Remove it when it is not required:

wp plugin delete burst-statistics

Disabling or removing the plugin is temporary risk reduction, not a substitute for upgrading. If the plugin must remain installed but inactive, restrict administrative and plugin-management access through existing controls, monitor the host closely, and schedule the upgrade as soon as possible.

Because exploitation has been reported, patching alone may be insufficient. Review:

  • Administrator accounts.
  • Application passwords.
  • Active sessions.
  • Installed plugins.
  • Modified themes.
  • Scheduled tasks.
  • WordPress configuration.
  • Hosting, database, CDN, WAF, and identity-provider logs.

Rotate administrator and application-password credentials if compromise is suspected. Invalidate sessions where supported.

Post-Incident Checklist

  1. Preserve relevant web-server, WAF, WordPress, and hosting logs.
  2. Identify requests containing Basic Authentication metadata or targeting MainWP-related functionality.
  3. Compare administrator accounts and capabilities with a known-good baseline.
  4. Review plugin and theme files for unauthorized changes.
  5. Inspect wp-content/uploads for unexpected executable files.
  6. Check scheduled tasks, cron entries, and outbound connections.
  7. Rotate affected credentials and application passwords.
  8. Rebuild from a trusted backup if administrative compromise or persistent web-shell activity is confirmed.

Do not rely only on the absence of obvious defacement. An attacker with administrator impersonation may create a quiet persistence mechanism, add a privileged account, alter a plugin, or harvest data without changing public content.

Technical Remediation Notes

The minimum remediation sequence for a single site is:

# Record current state
wp plugin get burst-statistics --field=name,version,status

# Upgrade to the latest available release
wp plugin update burst-statistics

# Verify the resulting version and status
wp plugin get burst-statistics --field=name,version,status

If the update cannot be performed immediately:

wp plugin deactivate burst-statistics

Before disabling or deleting the plugin on a production site, confirm that the action will not break a business-critical analytics workflow. Operational dependency should not justify continued exposure to an authentication bypass rated CVSS 9.8.

References

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Last verified: 2026-11-12

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