CVE-2023-5307Public exploitNetwork attack vector

Stored XSS via unsanitized forwarded IP header

Published Oct 31, 2023 · Updated Apr 22, 2025

Stored XSS in Contest Gallery before 21.2.8.1 allows remote attackers to inject scripts through an X-Forwarded-For header. During an unauthenticated frontend image upload, the plugin stores the unsanitized header value and later renders it without escaping in the administrator's Edit Gallery view. A gallery with a published upload form must accept the submission, and the script runs only when an administrator opens the affected gallery entry.

CVSS severity6.1
Medium
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Contest Gallery before 21.2.8.1 allows remote attackers to inject scripts through an X-Forwarded-For header. During an unauthenticated frontend image upload, the plugin stores the unsanitized header value and later renders it without escaping in the administrator's Edit Gallery view. A gallery with a published upload form must accept the submission, and the script runs only when an administrator opens the affected gallery entry.

The record

CVE
CVE-2023-5307
Published
Oct 31, 2023
Updated
Apr 22, 2025
Vendor
Wasiliy Strecker / ContestGallery developer
Product
Contest Gallery
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 31, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <21.2.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Wasiliy Strecker / ContestGallery developer · Contest Galleryversion=0 <21.2.8.1

Published CVSS scores

6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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