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CVE Record

CVE-2026-4127: Speedup Optimization <= 1.5.9 - Missing Authorization to Authenticated (Subscriber+) Plugin Settings Update via 'speedup01_enabled' AJAX Action

The Speedup Optimization plugin for WordPress is vulnerable to Missing Authorization in all versions up to and including 1.5.9. The `speedup01_ajax_enabled()` function, which handles the `wp_ajax_speedup01_enabled` AJAX action, does not perform any capability check via `current_user_can()` and also lacks nonce verification. This is in contrast to other AJAX handlers in the same plugin (e.g., `speedup01_ajax_install_iox` and `speedup01_ajax_delete_cache_file`) which properly check for `install_plugins` and `manage_options` capabilities respectively. This makes it possible for authenticated attackers, with Subscriber-level access and above, to enable or disable the site's optimization module by sending a POST request to admin-ajax.

MediumCVSS 4.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

A low-privileged WordPress user could change a Speedup Optimization plugin setting that enables or disables the site’s optimization module. This is not a data theft or takeover issue in the cited sources, but it can let untrusted account holders alter site behavior without authorization.

Executive priority

Treat as a routine but timely WordPress plugin remediation. Prioritize sites with public registration or many low-privileged users. Business risk is mainly unauthorized configuration change and possible performance or behavior disruption, not confirmed compromise.

Technical view

CVE-2026-4127 is a missing authorization issue in Speedup Optimization for WordPress, reported for versions up to and including 1.5.9. The speedup01_ajax_enabled() handler for wp_ajax_speedup01_enabled lacks a capability check and nonce verification, allowing authenticated Subscriber-level users or higher to update the optimization setting.

Likely exposure

Exposure is limited to WordPress sites running Speedup Optimization up to 1.5.9 with authenticated users, especially open registration, customer portals, or many Subscriber accounts.

Exploitation context

The source bundle does not indicate active exploitation, and KEV is false. Exploitation requires an authenticated account but no user interaction. Impact is described as low integrity impact: unauthorized enabling or disabling of the optimization module.

Researcher notes

The evidence points to CWE-862 in speedup01_ajax_enabled(). The cited description contrasts this handler with other AJAX handlers that check install_plugins or manage_options. No exploit-in-the-wild evidence or specific fixed version is provided in the bundle.

Mitigation direction

  • Identify WordPress sites using Speedup Optimization up to version 1.5.9.
  • Check the plugin vendor or WordPress.org page for a fixed release or guidance.
  • If no fix is available, consider disabling the plugin on higher-risk sites.
  • Limit or review untrusted Subscriber-level accounts until remediation is confirmed.
  • Monitor plugin setting changes and administrative AJAX activity where feasible.

Validation and detection

  • Confirm installed Speedup Optimization version on each WordPress site.
  • Review whether untrusted users can authenticate to the affected site.
  • Verify the referenced handler lacks capability and nonce checks in deployed code.
  • Confirm any updated version adds authorization and nonce validation before closing the finding.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-862: Authorization and privilege behavior lookup

Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2026-4127 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.3 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
4.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N2.81.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.3Medium
CVSS 3.1 vector shape for CVE-2026-4127Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
charlycharmSpeedup Optimization0unaffected
Weakness

CWE details

CWE-862

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-862 · source CWE mapping

Missing Authorization

Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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