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CVE Record

CVE-2021-36839: WordPress Social Media Follow Buttons Bar plugin <= 4.73 - Authenticated Stored Cross-Site Scripting (XSS) vulnerability

Authenticated (admin+) Stored Cross-Site Scripting (XSS) vulnerability in Social Media Follow Buttons Bar plugin <= 4.73 at WordPress.

MediumCVSS 4.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-36839 is a stored XSS issue in the WordPress Social Media Follow Buttons Bar plugin through version 4.73. An already-authenticated administrator could save script content that later runs in another user's browser. Business risk is limited by the admin-level requirement but still relevant on shared or poorly controlled WordPress sites.

Executive priority

Treat as moderate priority. It should not outrank unauthenticated or actively exploited vulnerabilities, but exposed WordPress sites using this plugin should be reviewed and remediated during the normal vulnerability cycle, faster where admin access is broadly delegated.

Technical view

The vulnerability is CWE-79 stored cross-site scripting with CVSS 3.1 score 4.8. The vector shows network reachability, low attack complexity, high privileges required, user interaction required, changed scope, and low confidentiality and integrity impact. The source bundle does not identify a fixed version or vulnerable parameter.

Likely exposure

Exposure is limited to WordPress installations running Space X-Chimp Social Media Follow Buttons Bar plugin version 4.73 or earlier. Sites without this plugin are not indicated as affected by the supplied sources.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. Exploitation requires admin-level authentication and user interaction, reducing broad internet-scale risk. Stored XSS can still matter where admin accounts are shared, delegated, or compromised.

Researcher notes

Evidence is sufficient for affected product, version boundary, CWE, and CVSS characteristics. Evidence is incomplete for exploit details, fixed version, and specific vulnerable field. Avoid assuming broader product impact beyond the named WordPress plugin through version 4.73.

Mitigation direction

  • Inventory WordPress sites for this plugin and version.
  • Check Patchstack and the WordPress plugin page for vendor remediation guidance.
  • Update the plugin if a fixed release is available from the vendor.
  • Disable or remove the plugin where it is not required.
  • Restrict administrator access and review delegated admin accounts.

Validation and detection

  • Confirm installed plugin version is not 4.73 or earlier.
  • Verify whether the plugin remains active on production WordPress sites.
  • Review WordPress admin users for unnecessary elevated privileges.
  • Check recent plugin settings/content changes for unexpected script-like entries.
  • Document remediation status for each affected WordPress instance.
Prepared
Confidence
medium
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-2021-36839 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
4.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/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
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
4.8CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N1.72.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.8Medium
CVSS 3.1 vector shape for CVE-2021-36839Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/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
Space X-ChimpSocial Media Follow Buttons Bar (WordPress plugin)<= 4.73Listed
Weakness

CWE details

CWE-79

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