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CVE Record

CVE-2026-2289: Taskbuilder <= 5.0.3 - Authenticated (Administrator+) Stored Cross-Site Scripting via 'Block Emails' Field

The Taskbuilder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 5.0.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

MediumCVSS 4.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-2289 is a stored cross-site scripting issue in the WordPress Taskbuilder plugin through version 5.0.3. It requires an authenticated administrator-level attacker and only applies to multisite sites or sites where WordPress unfiltered_html is disabled. Business urgency is moderate because privileges required are high, but malicious script could run for users viewing affected admin pages.

Executive priority

Treat as a moderate-priority WordPress hygiene issue. It is not known to be actively exploited and requires admin access, but it can weaken controls on sensitive WordPress environments. Prioritize sites with many administrators, multisite deployments, or prior admin account compromise concerns.

Technical view

Taskbuilder insufficiently sanitizes input and escapes output in admin email notification settings, specifically the “Block Emails” field. An Administrator+ user can store arbitrary script that executes when the injected page is accessed. CVSS is 4.4, vector AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N, CWE-79.

Likely exposure

Exposure is limited to WordPress sites running Taskbuilder versions up to and including 5.0.3, specifically multisite installations or installations with unfiltered_html disabled. Single-site WordPress deployments where administrators retain unfiltered_html may not be affected based on the CVE description.

Exploitation context

No active exploitation is stated in the provided sources, and this CVE is not listed as KEV. Exploitation requires administrator-level access, making external drive-by exploitation unlikely. The main concern is misuse by a compromised or malicious admin account in affected WordPress configurations.

Researcher notes

Evidence points to stored XSS in admin settings due to sanitization and escaping weaknesses. The WordPress Trac links identify relevant files and a changeset, but the provided bundle does not clearly name a fixed version. Avoid assuming broader impact beyond multisite or unfiltered_html-disabled installations.

Mitigation direction

  • Inventory WordPress sites for the Taskbuilder plugin and installed version.
  • If version is 5.0.3 or older, check WordPress plugin/vendor guidance for an update.
  • Restrict administrator access to trusted users only.
  • Review Taskbuilder admin email settings for unexpected content in the Block Emails field.
  • Monitor vendor and Wordfence references for confirmed fixed-version details.

Validation and detection

  • Confirm whether the site is WordPress multisite or has unfiltered_html disabled.
  • Check Taskbuilder plugin version on each WordPress installation.
  • Inspect the Block Emails admin setting for suspicious script-like content.
  • Review administrator account activity around Taskbuilder settings changes.
  • Verify remediation against vendor or WordPress repository release information.
Prepared
Confidence
high
Sources
8

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-79: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. 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-2026-2289 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
4.4 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/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
7Source 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
4.4CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N1.32.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.4Medium
CVSS 3.1 vector shape for CVE-2026-2289Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/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
taskbuilderTaskbuilder – Project Management & Task Management Tool With Kanban Board0unaffected
Weakness

CWE details

CWE-79

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

CWE-79 · source CWE mapping

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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