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No exploitation reportedFix available

CVE-2021-39181

No exploitation reported by the sources we read.

  • Published2021-09-01
  • Fixed in15.5.3 · 15.3.18
  • WeaknessCWE-91

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

OpenOlat is a web-based learning management system (LMS). Prior to version 15.3.18, 15.5.3, and 16.0.0, using a prepared import XML file (e.g. a course) any class on the Java classpath can be instantiated, including spring AOP bean factories. This can be used to execute code arbitrary code by the attacker. The attack requires an OpenOlat user account with the authoring role. It can not be exploited by unregistered users. The problem is fixed in versions 15.3.18, 15.5.3, and 16.0.0. There are no known workarounds aside from upgrading.

Timeline

dates in UTC
  1. 2021-09-0120:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-39181?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-39181?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Frentix openolat
BranchAffectedFixed in
15.5≥ 15.5.0, < 15.5.315.5.3
15.3< 15.3.1815.3.18

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Frentix openolat to 15.5.3 · 15.3.18

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CNACVSS 3.18.8read 2026-10-23
  • NVDCVSS 2.06.5read 2026-10-23
  • CNAweakness (CWE)CWE-91read 2026-10-23
  • FIRST EPSSEPSS score1.9 %2026-10-22

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-09-01
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-39181?

OpenOlat is a web-based learning management system (LMS). Prior to version 15.3.18, 15.5.3, and 16.0.0, using a prepared import XML file (e.g. a course) any class on the Java classpath can be instantiated, including spring AOP bean factories. This can be used to execute code arbitrary code by the attacker. The attack requires an OpenOlat user account with the authoring role. It can not be exploited by unregistered users. The problem is fixed in versions 15.3.18, 15.5.3, and 16.0.0. There are no known workarounds aside from upgrading.

Is CVE-2021-39181 actively exploited?

Active exploitation of CVE-2021-39181 has not been confirmed. Its EPSS score was 1.9% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-39181?

CVE-2021-39181 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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