How severe is CVE-2021-47840?

CVE-2021-47840 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-47840 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2021-47840?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2021-47840 have an EU (EUVD) identifier?

Yes. CVE-2021-47840 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-2868.

When was CVE-2021-47840 published?

CVE-2021-47840 was published on 2026-01-16 and last updated on 2026-06-17.

CVE-2021-47840

CVE-2021-47840 is a high-severity vulnerability with a CVSS 3.x base score of 7.2. 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: High (CVSS 3.x base score 7.2)
CVSS v4: 5.1
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-2868
Weakness: CWE-79
Published: 2026-01-16
Last modified: 2026-06-17

Description

Moeditor 0.2.0 contains a persistent cross-site scripting vulnerability that allows attackers to store malicious payloads within markdown files. Attackers can upload specially crafted markdown files with embedded JavaScript that execute when opened, potentially enabling remote code execution on the victim's system.

Frequently asked questions

What is CVE-2021-47840?: Moeditor 0.2.0 contains a persistent cross-site scripting vulnerability that allows attackers to store malicious payloads within markdown files. Attackers can upload specially crafted markdown files with embedded JavaScript that execute when opened, potentially enabling remote code execution on the victim's system.
How severe is CVE-2021-47840?: CVE-2021-47840 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-47840 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2021-47840?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-47840 have an EU (EUVD) identifier?: Yes. CVE-2021-47840 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-2868.
When was CVE-2021-47840 published?: CVE-2021-47840 was published on 2026-01-16 and last updated on 2026-06-17.

References

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

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CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
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CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

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