Security readout for executives and security teams
Plain-English summary
Some WordPress versions could leak error output from wp_die() through JSONP handling. The leaked data could include nonces, which may let an attacker perform actions as another user. The issue is medium severity because exploitation conditions are constrained, but exposed public WordPress sites should be updated promptly.
Executive priority
Treat this as a prompt maintenance security update, not an emergency based on current evidence. Prioritize public WordPress sites, customer-facing properties, and sites with many low-privilege users. The main business risk is unauthorized user actions enabled by leaked nonce data.
Technical view
CVE-2021-39200 is a CWE-200 information disclosure flaw in WordPress versions 5.2.0 through before 5.8.1. Under certain conditions, wp_die() output could be exposed via JSONP. CVSS 3.1 scores it 5.3, with network access, high attack complexity, low privileges required, and high confidentiality impact.
Likely exposure
Exposure is most likely on WordPress installations running versions >=5.2.0 and <5.8.1, including older maintained branches that missed the minor security release. Public internet-facing sites matter most, especially where untrusted low-privilege accounts exist.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Public disclosure exists through GitHub, HackerOne, CVE, and Debian advisories. The advisory says leaked nonces could be used to perform actions on a user's behalf, but exploitation conditions are described only generally.
Researcher notes
Evidence supports information disclosure through wp_die() JSONP behavior, with potential nonce exposure. The bundle does not provide complete exploit prerequisites or affected plugin interactions. Avoid assuming active exploitation or broader product impact beyond WordPress core versions listed in the advisory data.
Mitigation direction
- Update WordPress to 5.8.1 or the applicable patched minor release.
- Keep WordPress automatic security updates enabled.
- Apply Debian wordpress package updates if using Debian-maintained packages.
- Review vendor guidance for branch-specific upgrade paths.
- Temporarily reduce untrusted low-privilege access until patched.
Validation and detection
- Inventory WordPress installations and record exact core versions.
- Flag versions >=5.2.0 and <5.8.1 as affected.
- Confirm patched minor releases are installed across all branches.
- Check whether automatic security updates are enabled.
- Review exposed sites with untrusted user registration or contributor access.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-200: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupDatabase behavior lookup
The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-39200 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N1.63.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/WordPress/wordpress-develop/security/advisories/GHSA-m9hc-7v5q-x8q5CVE reference · x_refsource_CONFIRM
- https://hackerone.com/reports/1142140CVE reference · x_refsource_MISC
- DSA-4985CVE reference · vendor-advisory, x_refsource_DEBIAN
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Exposure of Sensitive Information to an Unauthorized Actor
Exposure of Sensitive Information to an Unauthorized Actor represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.