CVE-2023-6379Public exploitNetwork attack vector

Browser-session compromise via unencoded Mercury parameters

Published Dec 13, 2023 · Updated Oct 1, 2024

Reflected XSS in the Mercury template in Alkacon Software OpenCms 14 and 15 allows remote attackers to run JavaScript in a victim's browser. Multiple Mercury list, blog, diary, job-ad, and form pages return crafted page or input values in HTML without output encoding. No authentication is required, but a victim must open a crafted URL; the script can read session data and act within the victim's browser session.

CVSS severity5.4
Medium
EPSS probability1.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in the Mercury template in Alkacon Software OpenCms 14 and 15 allows remote attackers to run JavaScript in a victim's browser. Multiple Mercury list, blog, diary, job-ad, and form pages return crafted page or input values in HTML without output encoding. No authentication is required, but a victim must open a crafted URL; the script can read session data and act within the victim's browser session.

The record

CVE
CVE-2023-6379
Published
Dec 13, 2023
Updated
Oct 1, 2024
Vendor
Alkacon Software
Product
OpenCms
Classifications
CWE-79, CAPEC-63, T1539
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 13, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 2024Record 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=14
  2. Affected versionversion=15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Alkacon Software · OpenCmsversion=14; version=15

Published CVSS scores

5.4INCIBECVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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')
CAPEC-63Cross-Site Scripting (XSS)
T1539Browser Session Cookie

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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