CVE-2023-4220

Unrestricted file upload in big file upload functionality in `/main/inc/lib/javascript/bigupload/inc/bigUpload.php` in Chamilo LMS <= v1.11.24 allows unauthenticated attackers to perform stored cross-site scripting attacks and obtain remote code execution via uploading of web shell.

CVSS: 8.1Highscored by the publisher (CNA)
Exploited in the wild: Not knownPublic exploit code; not in CISA KEV
EPSS: 76.1%chance of exploitation in the next 30 daystop 0.5% of scored CVEsFIRST score of 11 Nov 2026
Fix: Patch availablesee the advisories in the references
Published: 28 Nov 2023analysed here 12 Nov 2026

Summary

Triage

Attack surface: Server and client
Exploitable: At runtime
Attack vector: network
Weaknesses: CWE-434 Unrestricted File Upload
CWE-79 Cross-Site Scripting (XSS)
Can a WAF block it?: Yes. See why

The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.

Affected products

Product	Affected versions	Vendor says fixed in
Chamilo	<= 1.11.24Vendor says fixed in: not stated	Not stated by the vendor

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

Products named in our analysis

chamilo:chamilo_lms

Fix and mitigation

WAF and other mitigations

Can a WAF block it? Yes. Cross-site scripting sends script tags or event handlers in the request, which WAF signatures match well.

Also consider: MIME sniff · sandbox storage · CSP · output encoding

Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

Remediation steps (AI-written)

Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.

Exploitation evidence

CISA KEV catalog: Not listed as of our last sync.
Public exploit code: Yes: 1 on Exploit-DB · 1 Metasploit module · 26 GitHub proofs of concept · 1 Nuclei template

and 22 more repositories

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

Timeline

28 Nov 2023Published
7 Jul 2024First public exploit or proof of concept222 days (about 7 months) later
2 Aug 2024CVE record last updated26 days later
12 Nov 2026Analysed by vulneraibility.com832 days (about 2 years) later

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Metric	Value	What it means
Attack vector	NetworkReachable over the internet or any routable network.	Reachable over the internet or any routable network.
Attack complexity	HighNeeds specific conditions, a race or a particular configuration.	Needs specific conditions, a race or a particular configuration.
Privileges required	NoneThe attacker needs no prior access.	The attacker needs no prior access.
User interaction	NoneNo victim action needed.	No victim action needed.
Scope	UnchangedImpact stays within the vulnerable component.	Impact stays within the vulnerable component.
Confidentiality	HighTotal data disclosure possible.	Total data disclosure possible.
Integrity	HighComplete modification possible.	Complete modification possible.
Availability	HighFull outage possible.	Full outage possible.

Common questions

Is CVE-2023-4220 being exploited?

Not confirmed. CVE-2023-4220 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 76% probability of exploitation in the next 30 days.

How severe is CVE-2023-4220?

CVE-2023-4220 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2023-4220?

Yes. A fix has been recorded for CVE-2023-4220. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2023-4220 affect?

CVE-2023-4220 affects chamilo:chamilo_lms. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

References

NVD CVE.org CVE Details Source

3 references in the CVE record, grouped by the tags the record gives them.

Advisories (2)

support.chamilo.org /projects/chamilo-18/wiki/security_issues#Issue-130-2023-09-04-Critical-impact-H
starlabs.sg /advisories/23/23-4220

Patches (1)

github.com /chamilo/chamilo-lms/commit/3b487a55076fb06f96809b790a35dcdd42f8ec49

Where the data on this page comes from

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
FIRST EPSS: exploit probability and percentile
Exploit-DB: published exploits
Metasploit Framework: exploit and scanner modules
Nuclei templates: detection templates
PoC-in-GitHub: GitHub repositories that claim a proof of concept

Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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