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

Exp

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.

Published: 2023-09-25 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-3550 is rated High Exploit Risk (67.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.15%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-3550

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-3550

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.18% 1.15% +0.97%
2 2026-01-05 0.09% 0.18% +0.10%
3 2025-11-21 — 0.09% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-3550

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.3 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.1 5.2 [email protected]
9.0 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.3 6.0 [email protected]

Weakness enumeration for CVE-2023-3550

OS Trackers for CVE-2023-3550

vendor priority summary link
debian not yet assigned CVE-2023-3550 not yet assigned priority: Debian including 1 source packages (mediawiki), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-3550
redhat medium — https://access.redhat.com/security/cve/CVE-2023-3550
ubuntu medium CVE-2023-3550 medium priority: Ubuntu including 1 source packages (mediawiki), 12 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 6, needs-triage 6. https://ubuntu.com/security/CVE-2023-3550

Affected software / configurations for CVE-2023-3550

Vendor Product Version Raw CPE
mediawiki mediawiki 1.40.0 cpe:2.3:a:mediawiki:mediawiki:1.40.0:-:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2023-3550

cvelogic Threat Intelligence