CVE-2026-78189: vulnerability in WebDyne
WebDyne versions from 3.007 before 3.022 for Perl execute .psp files outside the document root via path traversal in the PSGI API route fallback
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
3Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackepss 0.2%
WebDyne versions from 3.007 before 3.022 for Perl execute .psp files outside the document root via path traversal in the PSGI API route fallback.
When a request matches no file, the PSGI handler retries it as an API route through api_filename. That keeps .. segments in the request path and only checks that the joined path starts with the document root, which a request for /../private passes.
A remote attacker can run the embedded Perl in any .psp file the server can read, such as one uploaded to a directory outside the document root.
Affected products
WebDyneRelated CVEs — WebDyne
In the same product, most dangerous first.
CVE-2026-78191—WebDyne versions from 2.031 before 3.022 for Perl execute files with .psp anywhere in the name as Perl pagesEPSS 0.5%CVE-2026-78190—WebDyne versions from 2.014 before 3.022 for Perl reflect request parameters unescaped into form field values, allowing cross-site scriptingEPSS 0.2%CVE-2026-78192—WebDyne versions from 2.022 before 3.022 for Perl disclose application source to unauthenticated clients via the viewer in the default index pageEPSS 0.2%CVE-2026-78188—WebDyne versions from 2.014 before 3.022 for Perl issue session cookies without the Secure, HttpOnly and SameSite attributesEPSS 0.1%