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Vulnerabilities

Vulnerability · CVE-2026-28496

fossbilling fossbilling Improper Neutralization of Special Elements Used in a Template Engine

Published Jun 25, 2026 · catalog updated Jun 25, 2026 · fossbilling fossbilling Improper Neutralization

Patch now

CVE-2026-28496 is in the CISA known-exploited catalog. Confirm fossbilling fossbilling Improper Neutralization against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (fossbilling fossbilling Improper Neutralization).
  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Unknown—
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
1.91%
Remediation
Remediation guidance
Affected products
vendor fossbilling fossbilling

FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 have a Server-Side Template Injection (SSTI) vulnerability in the template rendering system. Administrators with access to features that render Twig templates (email templates, mass mail campaigns, custom payment adapters, and the API endpoint) can inject arbitrary Twig expressions, leading to information disclosure and remote code execution. The vulnerability exists because Twig templates are rendered without a sandbox, allowing access to the full Twig environment, API context, and the application VulnCheck canary evidence. Initial-access exploit intelligence.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor fossbilling fossbillingversion unspecified

How to fix CVE-2026-28496

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-28496 is in the CISA known-exploited catalog. Confirm fossbilling fossbilling Improper Neutralization against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

No weakness class is stored. EPSS 1.91%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 25, 2026 · VulnCheck KEV

    Detected

    FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 have a Server-Side Template Injection (SSTI) vulnerability in the template rendering system. Administrators with access to features that render Twig templates (email templates, mass mail campaigns, custom payment adapters, and the API endpoint) can inject arbitrary Twig expressions, leading to informat

  2. Jun 25, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Sources

  • CVE.orgVulnerability recordCVE-2026-28496

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-28496

    30-day exploitation probability 1.9%

    first.org
  • VulnCheck KEVConfirmed exploitationCVE-2026-28496

    FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 have a Server-Side Template Injection (SSTI) vulnerability in the template rendering system. Administrators with access to features that render Twig templates (email templates, mass m

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.