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CVE Record

CVE-2021-36841: YITH Maintenance Mode (WordPress plugin) <= 1.3.7 - Authenticated Stored Cross-Site Scripting (XSS) vulnerability.

Authenticated Stored Cross-Site Scripting (XSS) vulnerability in YITH Maintenance Mode (WordPress plugin) versions <= 1.3.7, vulnerable parameter &yith_maintenance_newsletter_submit_label. Possible even when unfiltered HTML is disallowed by WordPress configuration.

MediumCVSS 6.9Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-36841 is a stored XSS issue in the YITH Maintenance Mode WordPress plugin through version 1.3.7. A highly privileged authenticated user could save malicious content in a newsletter button label setting, potentially affecting another user who later views the rendered content.

Executive priority

Treat as a targeted WordPress hygiene issue, not an emergency internet-wide event. Prioritize sites using this plugin, especially customer-facing or admin-heavy sites, and remediate during the next maintenance cycle unless suspicious admin activity is found.

Technical view

The vulnerability is CWE-79 stored cross-site scripting in the yith_maintenance_newsletter_submit_label parameter. CVSS 3.1 is 6.9, with network attack vector, low complexity, high privileges required, user interaction required, and changed scope. The source notes it may occur even when WordPress disallows unfiltered HTML.

Likely exposure

Exposure is limited to WordPress sites running YITH Maintenance Mode version 1.3.7 or earlier. Risk is lower than unauthenticated XSS because attacker privileges are high, but impact can cross user boundaries once stored content is rendered.

Exploitation context

The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires an authenticated high-privilege actor and a second user interaction with affected rendered content. Evidence is insufficient to claim broad exploitation.

Researcher notes

The key uncertainty is fixed-version detail: the provided bundle identifies affected versions but does not provide a specific patched release. Researchers should confirm current vendor records before asserting a fix version. Avoid assuming unfiltered_html restrictions fully mitigate the issue.

Mitigation direction

  • Inventory WordPress sites for YITH Maintenance Mode installations.
  • Check installed plugin versions and flag version 1.3.7 or earlier.
  • Follow YITH or WordPress plugin guidance for updates or replacement.
  • Disable or remove the plugin where maintenance-mode functionality is unnecessary.
  • Restrict high-privilege WordPress accounts to trusted administrators only.

Validation and detection

  • Confirm no production site runs YITH Maintenance Mode 1.3.7 or earlier.
  • Review the newsletter submit label setting for unexpected markup or scripts.
  • Check privileged WordPress accounts for unauthorized or stale administrators.
  • Review recent administrative changes to plugin settings where logs exist.
  • Verify remediation against YITH, WordPress.org, or Patchstack guidance.
Prepared
Confidence
high
Sources
4

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-2021-36841 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
6.9 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/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
3Source 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
6.9CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N1.74.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.9Medium
CVSS 3.1 vector shape for CVE-2021-36841Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/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
YITHYITH Maintenance Mode (WordPress plugin)<= 1.3.7Listed
Weakness

CWE details

CWE-79

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