How severe is CVE-2020-35475?

CVE-2020-35475 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2020-35475 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-35475?

CVE-2020-35475 primarily affects Mediawiki. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-35475?

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.

When was CVE-2020-35475 published?

CVE-2020-35475 was published on 2020-12-18 and last updated on 2026-06-17.

CVE-2020-35475

CVE-2020-35475 is a high-severity vulnerability in Mediawiki with a CVSS 3.x base score of 7.5. 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 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Mediawiki
Published: 2020-12-18
Last modified: 2026-06-17

Description

In MediaWiki before 1.35.1, the messages userrights-expiry-current and userrights-expiry-none can contain raw HTML. XSS can happen when a user visits Special:UserRights but does not have rights to change all userrights, and the table on the left side has unchangeable groups in it. (The right column with the changeable groups is not affected and is escaped correctly.)

Frequently asked questions

What is CVE-2020-35475?: In MediaWiki before 1.35.1, the messages userrights-expiry-current and userrights-expiry-none can contain raw HTML. XSS can happen when a user visits Special:UserRights but does not have rights to change all userrights, and the table on the left side has unchangeable groups in it. (The right column with the changeable groups is not affected and is escaped correctly.)
How severe is CVE-2020-35475?: CVE-2020-35475 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2020-35475 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-35475?: CVE-2020-35475 primarily affects Mediawiki. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-35475?: 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.
When was CVE-2020-35475 published?: CVE-2020-35475 was published on 2020-12-18 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

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