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CVE-2026-34366 InvoiceShelf CVE debrief

A Server-Side Request Forgery (SSRF) vulnerability exists in InvoiceShelf, an open-source web & mobile app, prior to version 2.2.0. The vulnerability is located in the Payment receipt PDF generation module. User-supplied HTML in the payment Notes field is passed unsanitised to the Dompdf rendering library, which can fetch remote resources referenced in the markup. This issue allows for SSRF attacks directly via the PDF receipt endpoint, regardless of automated email attachments being enabled. The vulnerability has been patched in version 2.2.0. Users of InvoiceShelf should prioritize upgrading to mitigate SSRF risk.

Vendor
InvoiceShelf
Product
Unknown
CVSS
HIGH 7.6
CISA KEV
Not listed in stored evidence
Original CVE published
2026-03-31
Original CVE updated
2026-07-24
Advisory published
2026-03-31
Advisory updated
2026-07-24

Who should care

Users of InvoiceShelf, especially those who use the payment receipt PDF generation feature, should be aware of this vulnerability. Administrators and developers of InvoiceShelf should prioritize upgrading to version 2.2.0 or applying necessary patches to mitigate the risk of SSRF attacks. Vulnerability management and security teams should review exposure and plan remediation efforts.

Technical summary

The SSRF vulnerability in InvoiceShelf arises from unsanitized user-supplied HTML in the payment Notes field being passed to the Dompdf rendering library. This library can fetch remote resources referenced in the markup, allowing attackers to perform SSRF attacks directly via the PDF receipt endpoint. The vulnerability has a CVSS score of 7.6 and is classified as HIGH severity. Affected deployments should be identified and prioritized for patching to version 2.2.0 or later.

Defensive priority

High

Recommended defensive actions

  • Upgrade InvoiceShelf to version 2.2.0 or later
  • Restrict access to the PDF receipt endpoint
  • Implement input validation and sanitization for user-supplied HTML
  • Monitor for suspicious activity related to SSRF attacks
  • 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

Evidence notes

The CVE record was published on 2026-03-31T21:16:29.537Z and last modified on 2026-07-24T20:10:00.147Z. The NVD entry is currently Analyzed. Evidence is limited to CVE and NVD information. Defenders should verify InvoiceShelf version and PDF receipt endpoint exposure.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-34366 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-34366

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-34366 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-34366

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental 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.