CVE-2021-43687Network attack vector

Cross-site scripting via cookie hex decoding

Published Dec 1, 2021 · Updated Jul 9, 2026

Cross-site scripting in Chamilo LMS 1.11.14 allows remote attackers to execute script in a user's browser via a crafted cookie. The plugin/jcapture/applet.php endpoint decodes attacker-controlled hexadecimal cookie content and embeds the resulting bytes in generated applet HTML without context-safe escaping. Exploitation requires a victim to request the endpoint, after which script runs with the victim's web session and can read or alter data permitted to that session.

CVSS severity6.1
Medium
EPSS probability1.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Chamilo LMS 1.11.14 allows remote attackers to execute script in a user's browser via a crafted cookie. The plugin/jcapture/applet.php endpoint decodes attacker-controlled hexadecimal cookie content and embeds the resulting bytes in generated applet HTML without context-safe escaping. Exploitation requires a victim to request the endpoint, after which script runs with the victim's web session and can read or alter data permitted to that session.

The record

CVE
CVE-2021-43687
Published
Dec 1, 2021
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NVDCVSS: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 exploitUnconfirmed

Weakness, pattern, technique

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

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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