CVE-2018-20148 — In WordPress before 4

In WordPress before 4.9.9 and 5.x before 5.0.1, contributors could conduct PHP object injection attacks via crafted metadata in a wp.getMediaItem XMLRPC call. This is caused by mishandling of serialized data at phar:// URLs in the wp_get_attachment_thumb_file function in wp-inclu

01What is this vulnerability?

In WordPress before 4.9.9 and 5.x before 5.0.1, contributors could conduct PHP object injection attacks via crafted metadata in a wp.getMediaItem XMLRPC call. This is caused by mishandling of serialized data at phar:// URLs in the wp_get_attachment_thumb_file function in wp-includes/post.php.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2018-12-14T20:00:00.000Z
• Last modified: 2024-08-05T11:51:19.200Z

09References

• www.securityfocus.com — http://www.securityfocus.com/bid/106220
• wordpress.org — https://wordpress.org/support/wordpress-version/version-5-0-1/
• blog.secarma.co.uk — https://blog.secarma.co.uk/labs/near-phar-dangerous-unserialization-wherever-you…
• codex.wordpress.org — https://codex.wordpress.org/Version_4.9.9
• wpvulndb.com — https://wpvulndb.com/vulnerabilities/9171
• www.zdnet.com — https://www.zdnet.com/article/wordpress-vulnerability-affects-a-third-of-most-po…
• www.debian.org — https://www.debian.org/security/2019/dsa-4401
• wordpress.org — https://wordpress.org/news/2018/12/wordpress-5-0-1-security-release/
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2019/02/msg00019.html
• www.zdnet.com — https://www.zdnet.com/article/wordpress-plugs-bug-that-led-to-google-indexing-so…