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CVE Record

CVE-2021-39313: Simple Image Gallery <= 1.0.6 Reflected Cross-Site Scripting

The Simple Image Gallery WordPress plugin is vulnerable to Reflected Cross-Site Scripting via the msg parameter found in the ~/simple-image-gallery.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 1.0.6.

MediumCVSS 6.1Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a reflected cross-site scripting issue in a WordPress image gallery plugin. An attacker would need to get a user to interact with a crafted request. Successful abuse could run script in that user's browser context, creating limited confidentiality and integrity impact. No source provided evidence of active exploitation.

Executive priority

Treat as a moderate web application risk. It is not presented as actively exploited, but public WordPress exposure and user-interaction phishing make timely inventory and remediation appropriate.

Technical view

CVE-2021-39313 affects Simple Image Gallery WordPress plugin versions up to and including 1.0.6. The msg parameter in simple-image-gallery.php is vulnerable to reflected XSS. CVSS 3.1 is 6.1: network reachable, low complexity, no privileges, user interaction required, changed scope, with low confidentiality and integrity impact.

Likely exposure

Exposure is limited to WordPress sites with the Simple Image Gallery plugin installed at version 1.0.6 or earlier. Internet-facing sites increase phishing and session-abuse risk if authenticated users can be lured to crafted links.

Exploitation context

The source bundle marks this CVE as not in KEV and provides no cited evidence of active exploitation. The issue is still practically exploitable in principle because reflected XSS requires only a vulnerable endpoint and user interaction.

Researcher notes

Evidence supports reflected XSS through the msg parameter in simple-image-gallery.php for versions up to and including 1.0.6. The provided sources do not identify a specific fixed version, exploitation in the wild, or detailed vendor mitigation.

Mitigation direction

  • Inventory WordPress sites for Simple Image Gallery version 1.0.6 or earlier.
  • Check official plugin and Wordfence guidance for a fixed or supported version.
  • Disable or remove the plugin if no supported fix is available.
  • Limit exposure of affected WordPress sites where business operations allow.
  • Review security controls for reflected XSS detection and response.

Validation and detection

  • Confirm whether the Simple Image Gallery plugin is installed.
  • Record installed plugin versions and flag 1.0.6 or earlier.
  • Review simple-image-gallery.php handling of the msg parameter.
  • Check web logs for unusual requests involving the msg parameter.
  • Verify remediation against vendor or Wordfence 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-2021-39313 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
6.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/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
6.1CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.1Medium
CVSS 3.1 vector shape for CVE-2021-39313Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/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
Simple Image GallerySimple Image Gallery1.0.6Listed
Weakness

CWE details

CWE-79

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