CVE-2023-3550
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.
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
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 High
CVSS: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 High
CVSS: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 High
CVSS: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 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N - CVSS 3.1
- 9.0 Critical
CVSS: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 High
CVSS: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 High
CVSS: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 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N - CVSS 3.1
- 9.0 Critical
CVSS: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
| Package | Affected | Fixed |
|---|---|---|
mediawiki/corePackagist |
through 1.40.0 | None known |
mediawikiBitnami |
1.40.0 up to 1.40.1 | 1.40.1 |
mediawikiDebian: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 |
mediawikiDebian:13 |
before 1:1.39.5-1 | 1:1.39.5-1 |
mediawikiDebian:14 |
before 1:1.39.5-1 | 1:1.39.5-1 |
mediawikiDebian: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 less1:1.31.16-1+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 |
mediawikiDebian: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 less1:1.35.4-1~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 |
mediawikiDebian: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 |
mediawikiMageia:9 From an advisory covering 8 CVEs |
before 1.35.14-1.mga9 | 1.35.14-1.mga9 |
mediawikiUbuntu: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
| Package | Affected | Fixed |
|---|---|---|
mediawikiUbuntu: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 less1:1.31.5-3ubuntu11:1.31.6-11:1.31.7-11:1.31.7-1ubuntu0.1~esm1 |
None known |
mediawikiUbuntu: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 |
mediawikiUbuntu: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 |
mediawikiUbuntu: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 |
mediawikiUbuntu: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 |
mediawikiUbuntu: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
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases, products, published | EUVD | |
| first indexed | CVE 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
fluidattacks.com/advisories/blondie
mediawiki.org/wiki/MediaWiki
debian.org/security/2023/dsa-5520
lists.debian.org/debian-lts-announce/2023/11/msg00027.html
lists.fedoraproject.org/archives/list/[email protected]/message/FU2FGUXXK6TMV6R52VRECLC6XCSQQISY
nvd.nist.gov/vuln/detail/CVE-2023-3550
Show 8 moreShow less
github.com/advisories/GHSA-4pqg-hr8r-h5cw
github.com/CVEProject/cvelistV5/tree/main/cves/2023/3xxx/CVE-2023-3550.json
security-tracker.debian.org/tracker/CVE-2023-3550
advisories.mageia.org/MGASA-2024-0155.html
bugs.mageia.org/show_bug.cgi?id=33156
ubuntu.com/security/CVE-2023-3550
phabricator.wikimedia.org/T341565
cve.org/CVERecord?id=CVE-2023-3550