CVE-2026-12939

NVD: The Newsletters Lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'link' attribute of the post_thumbnail (and newsletters_post_thumbnail) shortcodes in versions up to and including 4.15. NVD: This is due to insufficient input sanitization and output escaping in the post_thumbnail() method in helpers/shortcode.php, which concatenates the user-controlled $link shortcode attribute directly into an href attribute without esc_url() or esc_attr(). NVD: This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Source-published summary

NVD: The Newsletters Lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'link' attribute of the post_thumbnail (and newsletters_post_thumbnail) shortcodes in versions up to and including 4.15. NVD: This is due to insufficient input sanitization and output escaping in the post_thumbnail() method in helpers/shortcode.php, which concatenates the user-controlled $link shortcode attribute directly into an href attribute without esc_url() or esc_attr(). NVD: This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Possible impact

Source describes XSS risk · authenticated boundary. Possible impact: This medium severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for XSS risk · authenticated boundary.

Affected context

Affected product or version requires source confirmation.

Remediation / advisory

Remediation reference present; patch status requires confirmation in the linked advisory.

Why it matters

Source describes XSS risk · authenticated boundary. Possible impact: This medium severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for XSS risk · authenticated boundary.; CVSS 6.4 (MEDIUM); EPSS percentile 12; not listed in KEV; Remediation reference present; patch status requires confirmation in the linked advisory; sources: NVD.

What to verify

Confirm affected product/version, vendor advisory, patch or mitigation, and exposure.

Exposure hint

authenticated boundary

Impact tags

Urgency reasons

Source-derived note

Summary derived from NVD description; unsafe procedural detail is not shown.

Redaction metadata

source summary used

True

fallback summary used

False

unsafe procedural detail present

false

raw source displayed

false

public summary redacted

true

Remediation handoff

Public-safe static handoff for human/Codex remediation planning. Scan, patch, external execution, and auto remediation are disabled.

Safety note

This radar shows source-published defensive context only. Exploit procedures, exploit strings, scanner commands, and auto-remediation are not provided.

Official references

• https://nvd.nist.gov/vuln/detail/CVE-2026-12939