Security readout for executives and security teams
Plain-English summary
This flaw lets an attacker run JavaScript in a victim’s browser if they can get the victim to open a crafted request involving the vulnerable WordPress plugin. It is not listed as actively exploited in the provided sources, but it can affect confidentiality and integrity for exposed WordPress sites using vulnerable versions.
Executive priority
Handle in normal vulnerability remediation cycles, faster for externally managed WordPress sites or administrator-heavy workflows. The issue is credible but not KEV-listed in the supplied evidence, so it is not an emergency absent local exploit indicators.
Technical view
CVE-2021-38356 is reflected XSS in NextScripts: Social Networks Auto-Poster through the request page parameter in inc/nxs_class_snap.php. The CVSS 3.1 score is 6.1, with network attack vector, low complexity, no privileges required, and required user interaction.
Likely exposure
Exposure is limited to WordPress sites running NextScripts: Social Networks Auto-Poster version 4.3.20 or earlier. The cited Wordfence title indicates broad installed-base concern, but the bundle does not prove which individual sites remain vulnerable now.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires user interaction and successful delivery of a crafted request, so phishing or administrator-targeted lures are the main concern rather than unaided server compromise.
Researcher notes
Evidence supports reflected XSS, CWE-79, and CVSS 6.1. The bundle names the vulnerable parameter and file but does not include a fixed version, patch diff, exploit-in-the-wild evidence, or current plugin availability status.
Mitigation direction
- Inventory WordPress sites for the NextScripts SNAP plugin and installed version.
- Update the plugin according to current vendor or WordPress plugin guidance.
- Disable or remove the plugin where no business need exists.
- Use WAF rules to reduce script-injection attempts against WordPress admin routes.
- Prioritize sites with administrator users likely to receive external links.
Validation and detection
- Confirm whether NextScripts SNAP version 4.3.20 or earlier is installed.
- Verify the vulnerable page parameter is not reflected unsafely after remediation.
- Review web logs for script-like input targeting plugin admin pages.
- Check that WordPress, plugins, and themes are centrally inventoried.
- Retest affected sites after updating or disabling the plugin.
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-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. 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 lookupCVE-2021-38356 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
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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:L/PR:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.wordfence.com/blog/2021/10/xss-vulnerability-in-nextscripts-social-networks-auto-poster-plugin-impacts-100000-sites/CVE reference · x_refsource_MISC
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.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.