Path traversal in WebDyne lets remote attackers run Perl .psp files
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.
Summary
WebDyne versions from 3.007 before 3.022 for Perl are affected. A path traversal flaw (CWE-22) in the PSGI API route fallback keeps .. segments in request paths and only checks that the joined path starts with the document root. A remote, unauthenticated attacker can run the embedded Perl in any .psp file the server can read, including files outside the document root.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | WebDyne | 3.007 to before 3.022 | 3.022 | Patch available | CNA |
- WebDyne Vendor— Affected 3.007 to before 3.022 Fixed in 3.022 Patch available CNA
Remediation
Upgrade WebDyne to version 3.022, which fixes this flaw.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA WebDyne Fixed in 3.022
Timeline
- 2026-10-31 Threatist record created from CVE-2026-78189
- 2026-10-31 Alias added: GHSA-vhwh-fhm6-mq7v
- 2026-11-06 CVSS score added · CISA ADP
- 2026-11-06 CISA SSVC decision points changed
- 2026-11-06 Priority changed: LOW → MEDIUM
References
Sources
- CVE-2026-78189 · CVE Program
- CVE-2026-78189 · NVD
- FIRST EPSS
- GHSA-vhwh-fhm6-mq7v · GitHub Advisory Database · CC BY 4.0
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