CVE-2026-78191 ASPEER CVE debrief

Who should care

Defenders of systems using WebDyne versions from 2.031 before 3.022 should assess exposure and prioritize remediation, focusing on verifying inventory for vulnerable WebDyne deployments and ensuring proper file extension validation. This includes operators, platform administrators, vulnerability management teams, and security teams who need to verify the presence of vulnerable WebDyne deployments and take appropriate actions.

Why it matters

CVE-2026-78191 allows remote attackers to execute Perl code through file upload. Defenders should assess exposure, prioritize remediation, and verify inventory for vulnerable WebDyne deployments.

• Remote code execution through file upload
• Potential for embedded Perl execution
• Need for careful file extension validation
• Verification of WebDyne version and configuration

Technical summary

WebDyne versions from 2.031 before 3.022 execute files with .psp anywhere in the name as Perl pages. An application that accepts uploads by checking only the final extension lets a remote attacker upload a file such as report.psp.pdf and run its embedded Perl by requesting it. This allows remote attackers to execute Perl code through file upload. Defenders should assess exposure, prioritize remediation, and verify inventory for vulnerable WebDyne deployments, focusing on proper file extension validation and verification of WebDyne version and configuration.

Defensive priority

Assess exposure, prioritize remediation

Recommended defensive actions

• Assess exposure to WebDyne versions from 2.031 before 3.022
• Prioritize remediation for affected systems
• Verify inventory for vulnerable WebDyne deployments
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide limited information about the vulnerability. WebDyne versions from 2.031 before 3.022 execute files with .psp anywhere in the name as Perl pages. The vulnerability allows remote attackers to upload a file such as report.psp.pdf and run its embedded Perl by requesting it. Defenders should verify inventory for vulnerable WebDyne deployments and ensure proper file extension validation. The CVE record was published on 2026-10-31T15:16:54.247Z and has not been modified since then.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.