CVE-2018-20149

In WordPress before 4.9.9 and 5.x before 5.0.1, when the Apache HTTP Server is used, authors could upload crafted files that bypass intended MIME type restrictions, leading to XSS, as demonstrated by a .jpg file without JPEG data.

Published: 2018-12-14 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-20149 is rated Moderate Risk (51.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 3.44%). Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2018-20149

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 4.43% 3.44% -0.98%
2 2026-03-04 3.53% 4.43% +0.89%
3 2026-03-01 — 3.53% —

Full EPSS history (41 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-20149

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2018-20149

OS Trackers for CVE-2018-20149

vendor priority summary link
debian not yet assigned CVE-2018-20149 not yet assigned priority: Debian including 1 source packages (wordpress), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-20149
ubuntu medium CVE-2018-20149 medium priority: Ubuntu including 1 source packages (wordpress), 19 status rows across 19 suites (bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 14, needed 2, DNE 1, ignored 1, released 1. https://ubuntu.com/security/CVE-2018-20149

Affected software / configurations for CVE-2018-20149

Vendor Product Version Raw CPE
wordpress wordpress < 4.9.9 cpe:2.3:a:wordpress:wordpress:*:*:*:*:*:*:*:*
wordpress wordpress >= 5.0, < 5.0.1 cpe:2.3:a:wordpress:wordpress:*:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

References for CVE-2018-20149

URL Tags
http://www.securityfocus.com/bid/106220 Third Party Advisory VDB Entry
https://codex.wordpress.org/Version_4.9.9 Product Vendor Advisory
https://github.com/WordPress/WordPress/commit/246a70bdbfac3bd45ff71c7941deef1bb206b19a Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2019/02/msg00019.html Mailing List Third Party Advisory
https://wordpress.org/news/2018/12/wordpress-5-0-1-security-release/ Release Notes Vendor Advisory
https://wordpress.org/support/wordpress-version/version-5-0-1/ Release Notes Vendor Advisory
https://wpvulndb.com/vulnerabilities/9175 Vendor Advisory
https://www.debian.org/security/2019/dsa-4401 Third Party Advisory
https://www.zdnet.com/article/wordpress-plugs-bug-that-led-to-google-indexing-some-user-passwords/ Press/Media Coverage Third Party Advisory
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