CVE-2020-35479

medium

Published — · Modified —

CVSS v3

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CVSS v2

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VIR risk

5.5

Description

MediaWiki before 1.35.1 allows XSS via BlockLogFormatter.php. Language::translateBlockExpiry itself does not escape in all code paths. For example, the return of Language::userTimeAndDate is is always unsafe for HTML in a month value. This affects MediaWiki 1.12.0 and later.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-35479

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-202101-22

OS impact

OS	Version	Status	Fixed in
arch		fixed	`1.35.1-1`
debian	bookworm	fixed	`1:1.35.1-1`
debian	bullseye	fixed	`1:1.35.1-1`
debian	forky	fixed	`1:1.35.1-1`
debian	sid	fixed	`1:1.35.1-1`
debian	trixie	fixed	`1:1.35.1-1`

References

https://security.archlinux.org/ASA-202101-22
https://security-tracker.debian.org/tracker/CVE-2020-35479

Verify integrity in audit chain (admin only). AS-IS.