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CVE-2023-3550

Stored XSS leads to privilege escalation in MediaWiki v1.40.0

7.3 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
Required

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
None

Exploit likelihood

1.38%Up 1.3 points since Sep 26, 2023
90%50%10%1%

What each source reports

CVE List Score used 7.3

Stored XSS leads to privilege escalation in MediaWiki v1.40.0

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.

Record
CVE-2023-3550
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-79
Updated
2026-11-02
EUVDEUVD-2023-44206 7.3

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.

Record
EUVD-2023-44206
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-03
GitHub AdvisoriesGHSA-4pqg-hr8r-h5cw 7.3

MediaWiki malicious XML upload leads to privilege escalation

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.

Record
GHSA-4pqg-hr8r-h5cw
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-79
Updated
2026-11-02
NVD 7.3

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.

Record
CVE-2023-3550
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
CVSS 3.1
9.0 CriticalCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Weakness
CWE-79
Updated
2026-11-02
OSV 7.3

Stored XSS leads to privilege escalation in MediaWiki v1.40.0

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.

Record
CVE-2023-3550
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-79
Updated
2026-11-02
OSVDEBIAN-CVE-2023-3550 7.3

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.

Record
DEBIAN-CVE-2023-3550
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
OSVUBUNTU-CVE-2023-3550 7.3

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.

Record
UBUNTU-CVE-2023-3550
CVSS 3.1
7.3 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
CVSS 3.1
9.0 CriticalCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Updated
2026-11-02
OSVBIT-mediawiki-2023-3550 No score

Stored XSS leads to privilege escalation in MediaWiki v1.40.0

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.

Record
BIT-mediawiki-2023-3550
Updated
2026-11-02
OSVMGASA-2024-0155 No score

Updated mediawiki packages fix security vulnerabilities

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. (CVE-2023-3550) An issue was discovered in MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. There is XSS in youhavenewmessagesmanyusers and youhavenewmessages i18n messages. This is related to MediaWiki:Youhavenewmessagesfromusers. (CVE-2023-45360) An issue was discovered in DifferenceEngine.php in MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. diff-multi-sameuser (aka "X intermediate revisions by the same user not shown") ignores username suppression. This is an information leak. (CVE-2023-45362) An issue was discovered in ApiPageSet.php in MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. It allows attackers to cause a denial of service (unbounded loop and RequestTimeoutException) when querying pages redirected to other variants with redirects and converttitles set. (CVE-2023-45363) An issue was discovered in includes/page/Article.php in MediaWiki 1.36.x through 1.39.x before 1.39.5 and 1.40.x before 1.40.1. Deleted revision existence is leaked due to incorrect permissions being checked. This reveals that a given revision ID belonged to the given page title, and its timestamp, both of which are not supposed to be public information. (CVE-2023-45364) An issue was discovered in MediaWiki before 1.35.14, 1.36.x through 1.39.x before 1.39.6, and 1.40.x before 1.40.2. In includes/logging/RightsLogFormatter.php, group-*-member messages can result in XSS on Special:log/rights. (CVE-2023-51704)

Record
MGASA-2024-0155
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
mediawiki/core
Packagist
through 1.40.0 None known
mediawiki
Bitnami
1.40.0 up to 1.40.1
1.40.1
mediawiki
Debian:12
before 1:1.39.5-1~deb12u1, plus listed versions
1:1.39.2-11:1.39.4-11:1.39.4-1~deb12u11:1.39.4-2
1:1.39.5-1~deb12u1
mediawiki
Debian:13
before 1:1.39.5-1
1:1.39.5-1
mediawiki
Debian:14
before 1:1.39.5-1
1:1.39.5-1
mediawiki
Debian:10
From an advisory covering 3 CVEs
before 1:1.31.16-1+deb10u7, plus listed versions
1:1.31.10-1~deb10u11:1.31.12-1~deb10u11:1.31.14-1~deb10u11:1.31.16-1+deb10u21:1.31.16-1+deb10u3
Show 15 moreShow less
1:1.31.16-1+deb10u41:1.31.16-1+deb10u51:1.31.16-1+deb10u61:1.31.16-1~deb10u11:1.31.2-11:1.31.4-11:1.31.4-1~deb10u11:1.31.5-11:1.31.5-21:1.31.5-31:1.31.6-11:1.31.6-1~deb10u11:1.31.7-11:1.31.7-1~deb10u11:1.31.8-1
1:1.31.16-1+deb10u7
mediawiki
Debian:11
From an advisory covering 4 CVEs
before 1:1.35.13-1~deb11u1, plus listed versions
1:1.35.11-1~deb11u11:1.35.2-11:1.35.3-11:1.35.4-11:1.35.4-1+deb11u2
Show 8 moreShow less
1:1.35.4-1~deb11u11:1.35.5-11:1.35.5-21:1.35.6-11:1.35.7-11:1.35.8-11:1.35.8-1.11:1.35.8-1~deb11u1
1:1.35.13-1~deb11u1
mediawiki
Debian:12
From an advisory covering 4 CVEs
before 1:1.39.5-1~deb12u1, plus listed versions
1:1.39.2-11:1.39.4-11:1.39.4-1~deb12u11:1.39.4-2
1:1.39.5-1~deb12u1
mediawiki
Mageia:9
From an advisory covering 8 CVEs
before 1.35.14-1.mga9
1.35.14-1.mga9
mediawiki
Ubuntu:18.04:LTS
All versions, plus listed versions
1:1.27.3-11:1.27.4-11:1.27.4-21:1.27.4-3
None known
Show 6 moreShow less
Affected packages
PackageAffectedFixed
mediawiki
Ubuntu:Pro:20.04:LTS
All versions, plus listed versions
1:1.31.2-1ubuntu11:1.31.5-11:1.31.5-1ubuntu11:1.31.5-21:1.31.5-3
Show 4 moreShow less
1:1.31.5-3ubuntu11:1.31.6-11:1.31.7-11:1.31.7-1ubuntu0.1~esm1
None known
mediawiki
Ubuntu:Pro:22.04:LTS
All versions, plus listed versions
1:1.35.3-11:1.35.4-11:1.35.5-11:1.35.5-1ubuntu11:1.35.5-1ubuntu21:1.35.5-1ubuntu31:1.35.6-11:1.35.6-1ubuntu0.1~esm1
None known
mediawiki
Ubuntu:Pro:24.04:LTS
All versions, plus listed versions
1:1.39.4-21:1.39.5-11:1.39.6-11:1.39.7-11:1.39.7-1ubuntu0.1~esm1
None known
mediawiki
Ubuntu:25.10
All versions, plus listed versions
1:1.43.1+dfsg-11:1.43.1+dfsg-21:1.43.3+dfsg-1
None known
mediawiki
Ubuntu:26.10
All versions, plus listed versions
1:1.43.8+dfsg-21:1.43.9+dfsg-11:1.43.9+dfsg-1ubuntu1
None known
mediawiki
Ubuntu:26.04:LTS
All versions, plus listed versions
1:1.43.3+dfsg-11:1.43.5+dfsg-11:1.43.6+dfsg-21:1.43.8+dfsg-11:1.43.8+dfsg-2
None known

History

History
RecordedChangedSources
affected, facts
aliases, products, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-3550 is a high vulnerability (CVSS 7.3) in Mediawiki, published September 25, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.38%, the 72nd percentile. Fixed in mediawiki 1.40.1.

References

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