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CVE Record

CVE-2023-0147: Flexible Captcha <= 4.1 - Contributor+ Stored XSS

The Flexible Captcha WordPress plugin through 4.1 does not validate and escape some of its shortcode attributes before outputting them back in a page/post where the shortcode is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks

MediumCVSS 5.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2023-0147 is a stored cross-site scripting issue in the Flexible Captcha WordPress plugin through version 4.1. A Contributor-level user or higher could place unsafe shortcode attributes into content, causing script execution when someone views the page.

Executive priority

Treat as a moderate priority for WordPress environments with many content contributors. It is not known exploited from the provided sources, but stored XSS can affect administrators and site visitors.

Technical view

The plugin does not validate and escape some shortcode attributes before outputting them in embedded posts or pages. The issue maps to CWE-79 and has CVSS 3.1 score 5.4. It requires authenticated low-privilege access and user interaction, with scope change and low confidentiality/integrity impact.

Likely exposure

Exposure is likely limited to WordPress sites using Flexible Captcha through 4.1 where Contributor or higher accounts can create content containing the plugin shortcode.

Exploitation context

The source bundle includes a WPScan technical reference tagged as exploit, but CISA KEV status is false and no provided source confirms active exploitation in the wild.

Researcher notes

The evidence identifies Flexible Captcha through 4.1 and the vulnerable pattern, but does not name a patched version or vendor mitigation. Validation should focus on plugin presence, shortcode content, and role-based exposure.

Mitigation direction

  • Inventory WordPress sites for Flexible Captcha through version 4.1.
  • Check vendor or plugin repository guidance for a fixed release.
  • Restrict Contributor and higher publishing access to trusted users.
  • Disable or remove the plugin where it is not required.
  • Review existing shortcode usage for suspicious attributes.

Validation and detection

  • Confirm whether Flexible Captcha is installed and identify its version.
  • Review posts and pages using Flexible Captcha shortcodes.
  • Audit users with Contributor or higher roles.
  • Inspect content revisions for unexpected script-like shortcode attributes.
  • Monitor reports from WPScan and CVE for remediation updates.
Prepared
Confidence
high
Sources
3

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.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2023-0147 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
5.4 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/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
2Source 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
5.4CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N2.32.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.4Medium
CVSS 3.1 vector shape for CVE-2023-0147Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:L/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
UnknownFlexible Captcha0affected
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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