How severe is CVE-2020-27621?

CVE-2020-27621 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2020-27621 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27621?

CVE-2020-27621 affects Mediawiki. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-27621?

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

When was CVE-2020-27621 published?

CVE-2020-27621 was published on 2020-10-22 and last updated on 2026-06-17.

CVE-2020-27621

CVE-2020-27621 is a medium-severity vulnerability in Mediawiki with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Mediawiki
Published: 2020-10-22
Last modified: 2026-06-17

Description

The FileImporter extension in MediaWiki through 1.35.0 was not properly attributing various user actions to a specific user's IP address. Instead, for various actions, it would report the IP address of an internal Wikimedia Foundation server by omitting X-Forwarded-For data. This resulted in an inability to properly audit and attribute various user actions performed via the FileImporter extension.

Frequently asked questions

What is CVE-2020-27621?: The FileImporter extension in MediaWiki through 1.35.0 was not properly attributing various user actions to a specific user's IP address. Instead, for various actions, it would report the IP address of an internal Wikimedia Foundation server by omitting X-Forwarded-For data. This resulted in an inability to properly audit and attribute various user actions performed via the FileImporter extension.
How severe is CVE-2020-27621?: CVE-2020-27621 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2020-27621 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27621?: CVE-2020-27621 affects Mediawiki. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-27621?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-27621 published?: CVE-2020-27621 was published on 2020-10-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*

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