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NVD / CVE Program· CNA GitHub_M

CVE-2021-29447: WordPress Authenticated XXE attack when installation is running PHP 8

Noroxi assessment

Priority: Plan (action score 52/100)

  • Public proof-of-concept code exists (Exploit-DB, GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 85.7% (FIRST EPSS); higher than 99.7% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: wordpress (Debian:10) 5.0.12+dfsg1-0+deb10u1; wordpress (Debian:12) 5.7.1+dfsg1-1; wordpress (Debian:9) 4.7.20+dfsg-1+deb9u1.

Add it to your regular patch cycle. Upgrade to wordpress (Debian:10) 5.0.12+dfsg1-0+deb10u1; wordpress (Debian:12) 5.7.1+dfsg1-1; wordpress (Debian:9) 4.7.20+dfsg-1+deb9u1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Wordpress is an open source CMS. A user with the ability to upload files (like an Author) can exploit an XML parsing issue in the Media Library leading to XXE attacks. This requires WordPress installation to be using PHP 8. Access to internal files is possible in a successful XXE attack. This has been patched in WordPress version 5.7.1, along with the older affected versions via a minor release. We strongly recommend you keep auto-updates enabled.

MediumCVSS 6.5 · v3.1—Proof of concept Fix available
Published
Apr 15, 2021
Updated
Jun 16, 2026
EPSS
85.7% · 99th percentile

Report tools

JSON

Action score

52

Plan

Add it to your regular patch cycle.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
26 / 30 · 85.7%

CNA vs NVD score

NVD
6.5
CNA · GitHub_M
7.1
0.6 point gap

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Is WordPress on your site?

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Is WordPress on your site?

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
wordpresswordpress
debiandebian linux

Using wordpress? Add it to your stack and be the first to know about CVEs like this one. (WordPress)

Watch new CVEs for wordpress

When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or gets exploit code

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every Monday

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • wordpress wordpress5.6.0 and later · before 5.7.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • WordPress wordpress-develop

    • >= 5.6.0, < 5.7.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:10wordpressbefore 5.0.12+dfsg1-0+deb10u15.0.12+dfsg1-0+deb10u1
Debian:12wordpressbefore 5.7.1+dfsg1-15.7.1+dfsg1-1
Debian:9wordpressbefore 4.7.20+dfsg-1+deb9u14.7.20+dfsg-1+deb9u1

Same product

wordpress: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-87902An unauthenticated attacker can make `get_page_template()` page-template resolution include a chosen readable local `.php` file outside the KEV
    91Now
  • CVE-2026-63030WordPress < 7.0.2 - REST API batch-route confusion and SQL injection issue leading to Remote Code ExecutionKEV
    72This week
  • CVE-2026-60137WordPress < 7.0.2 - Facilitated SQL Injection via author__not_in in WP_QueryKEV
    60This week

Published before and after this one in the same product

  • ← EarlierCVE-2020-28039Nov 2, 2020 · is_protected_meta in wp-includes/meta.php in WordPress before 5.5.2 allows arbitrary file deletion because it does not properly determine wh
    37Monitor
  • ← EarlierCVE-2020-28040Nov 2, 2020 · WordPress before 5.5.2 allows CSRF attacks that change a theme's background image.
    17Monitor
  • Later →CVE-2021-29450Apr 15, 2021 · WordPress Authenticated disclosure of password-protected posts and pages
    18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:wordpress5.7.1+dfsg1-1 · Debian:12Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×1
  • Proof-of-concept repository on GitHub ×24

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entrywebapps2021-09-20
Proof-of-concept repository on GitHubstars:442021-04-16
Proof-of-concept repository on GitHubstars:42021-05-23
Proof-of-concept repository on GitHubstars:32021-06-01
Proof-of-concept repository on GitHubstars:02021-08-27
Proof-of-concept repository on GitHubstars:12022-11-05
Proof-of-concept repository on GitHubstars:32022-11-06
Proof-of-concept repository on GitHubstars:12022-11-06
Proof-of-concept repository on GitHubstars:42022-11-11
Proof-of-concept repository on GitHubstars:72022-11-14
Proof-of-concept repository on GitHubstars:32022-11-15
Proof-of-concept repository on GitHubstars:22022-11-17

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoCsame day
  3. TodayNov 1, 2026+2026 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-611 · Improper Restriction of XML External Entity Reference

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records