How severe is CVE-2026-34161?

CVE-2026-34161 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-34161 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34161?

CVE-2026-34161 primarily affects Chamilo Chamilo Lms. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-34161?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-34161 have an EU (EUVD) identifier?

Yes. CVE-2026-34161 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22714.

When was CVE-2026-34161 published?

CVE-2026-34161 was published on 2026-04-14 and last updated on 2026-06-17.

CVE-2026-34161

CVE-2026-34161 is a medium-severity vulnerability in Chamilo Chamilo Lms with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v4: 5.1
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-22714
Weakness: CWE-79
Affected product: Chamilo Chamilo Lms
Published: 2026-04-14
Last modified: 2026-06-17

Description

Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, a Stored Cross-Site Scripting (XSS) vulnerability exists in the social post attachment upload functionality, where an authenticated user can upload a malicious HTML file containing JavaScript via the /api/social_post_attachments endpoint. The uploaded file is served back from the application at the generated contentUrl without sanitization, content type restrictions, or a Content-Disposition: attachment header, causing the JavaScript to execute in the browser within the application's origin. Because the payload is stored server-side and runs in the trusted origin, an attacker can perform session hijacking, account takeover, privilege escalation (if an admin views the link), and arbitrary actions on behalf of the victim. This issue has been fixed in version 2.0.0-RC.3.

Frequently asked questions

What is CVE-2026-34161?: Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, a Stored Cross-Site Scripting (XSS) vulnerability exists in the social post attachment upload functionality, where an authenticated user can upload a malicious HTML file containing JavaScript via the /api/social_post_attachments endpoint. The uploaded file is served back from the application at the generated contentUrl without sanitization, content type restrictions, or a Content-Disposition: attachment header, causing the JavaScript to execute in the browser within the application's origin. Because the payload is stored server-side and runs in the trusted origin, an attacker can perform session hijacking, account takeover, privilege escalation (if an admin views the link), and arbitrary actions on behalf of the victim. This issue has been fixed in version 2.0.0-RC.3.
How severe is CVE-2026-34161?: CVE-2026-34161 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-34161 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34161?: CVE-2026-34161 primarily affects Chamilo Chamilo Lms. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-34161?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34161 have an EU (EUVD) identifier?: Yes. CVE-2026-34161 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22714.
When was CVE-2026-34161 published?: CVE-2026-34161 was published on 2026-04-14 and last updated on 2026-06-17.

References

Affected products (11)

cpe:2.3:a:chamilo:chamilo_lms:*:*:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha1:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha2:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha3:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha4:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha5:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta1:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta2:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta3:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc1:*:*:*:*:*:*
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc2:*:*:*:*:*:*

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