CVE-2020-35478

MEDIUMNVD 6.16.1—

6.1

MediaWiki before 1.35.1 allows XSS via BlockLogFormatter.php. MediaWiki:blanknamespace potentially can be output as raw HTML with SCRIPT tags via LogFormatter::makePageLink(). This affects MediaWiki 1.33.0 and later.

CVSS v3: 6.1
EG Score: 6.1(medium)
EPSS: 63.8%
KEV: Not listed

Published

December 18, 2020

Last Modified

November 21, 2024

References (6)

cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/STT5Z4A3BCXVH3WIPICWU2FP4IPIMUPC/
cve@mitrehttps://lists.wikimedia.org/pipermail/mediawiki-announce/2020-December/000268.html
cve@mitrehttps://phabricator.wikimedia.org/T268938
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/STT5Z4A3BCXVH3WIPICWU2FP4IPIMUPC/
af854a3a-2127-422b-91ae-364da2661108https://lists.wikimedia.org/pipermail/mediawiki-announce/2020-December/000268.html
af854a3a-2127-422b-91ae-364da2661108https://phabricator.wikimedia.org/T268938

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-79Cross-site Scripting (XSS)

Data Freshness Timeline

(refreshed 13× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

2026-06-08 14:15 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-07 10:59 UTCOSV refresh
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:45 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 06:08 UTCEPSS rescore
2026-06-05 06:08 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore
2026-05-29 13:42 UTCEPSS rescore

Frequently asked(5)

What is CVE-2020-35478?

CVE-2020-35478 is a medium vulnerability published on December 18, 2020. MediaWiki before 1.35.1 allows XSS via BlockLogFormatter.php. MediaWiki:blanknamespace potentially can be output as raw HTML with SCRIPT tags via LogFormatter::makePageLink(). This affects MediaWiki 1.33.0 and later.

When was CVE-2020-35478 disclosed?

CVE-2020-35478 was first published in the National Vulnerability Database on December 18, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2020-35478 actively exploited?

CVE-2020-35478 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 63.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2020-35478?

CVE-2020-35478 has a CVSS v3 base score of 6.1 (NVD).

How do I remediate CVE-2020-35478?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-35478, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2020-35478

📅 Published

🔄 Last Modified

🔗 References (6)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2020-35478?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (6)

Frequently asked(5)

Related CVEs(same CWE)