What’s Vulnerable › Vulnerabilities

CVE-2023-3550: Stored XSS leads to privilege escalation in MediaWiki v1.40.0

• Severity: high (CVSS 7.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-09-25 · updated 2026-06-17
• Weakness: CWE-79

Description

Mediawiki v1.40.0 does not validate namespaces used in XML files. Therefore, if the instance administrator allows XML file uploads, a remote attacker with a low-privileged user account can use this exploit to become an administrator by sending a malicious link to the instance administrator.

Affected products

• Debian Linux: 10.0, 11.0
• Wikimedia Foundation MediaWiki: 1.40.0

References

• https://fluidattacks.com/advisories/blondie/
• https://lists.debian.org/debian-lts-announce/2023/11/msg00027.html
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FU2FGUXXK6TMV6R52VRECLC6XCSQQISY/
• https://www.debian.org/security/2023/dsa-5520
• https://www.mediawiki.org/wiki/MediaWiki/
• https://fluidattacks.com/advisories/blondie/
• https://lists.debian.org/debian-lts-announce/2023/11/msg00027.html
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FU2FGUXXK6TMV6R52VRECLC6XCSQQISY/
• https://www.debian.org/security/2023/dsa-5520
• https://www.mediawiki.org/wiki/MediaWiki/

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