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Vulnerabilities

Vulnerability · CVE-2026-0809

Use of a custom token encoding algorithm in Streamsoft Prestiż software allows the value of the KSeF (Krajowy System e-Faktur) token to be guessed after analyzing how tokens with k

Published Mar 12, 2026 · catalog updated Jun 17, 2026 · Streamsoft Streamsoft Prestiż

Last checked Nov 13, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-0809. EPSS is 0.29%. Act only if a listed version of Streamsoft Streamsoft Prestiż is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.29%
Remediation
Version ranges on file
Affected products
vendor Streamsoft Streamsoft Prestiż 12.2.363.17 <20.0.380.92

Use of a custom token encoding algorithm in Streamsoft Prestiż software allows the value of the KSeF (Krajowy System e-Faktur) token to be guessed after analyzing how tokens with know values are encoded. This issue was fixed in version 20.0.380.92.

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 Streamsoft Streamsoft Prestiż 12.2.363.17 <20.0.380.9212.2.363.17 <20.0.380.92

How to fix CVE-2026-0809

What to do

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

Should you patch?

No confirmed exploitation is on record for CVE-2026-0809. EPSS is 0.29%. Act only if a listed version of Streamsoft Streamsoft Prestiż is installed.

Which versions are affected?

Compare what you have installed with Streamsoft Streamsoft Prestiż 12.2.363.17 <20.0.380.92 12.2.363.17 <20.0.380.92. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-261. EPSS 0.29%. There is no CISA KEV listing. 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. Mar 12, 2026 · NIST NVD

    Detected

    Use of a custom token encoding algorithm in Streamsoft Prestiż software allows the value of the KSeF (Krajowy System e-Faktur) token to be guessed after analyzing how tokens with know values are encoded. This issue was fixed in version 20.0.380.92.

  2. Jun 17, 2026 · NIST NVD

    Updated

    Use of a custom token encoding algorithm in Streamsoft Prestiż software allows the value of the KSeF (Krajowy System e-Faktur) token to be guessed after analyzing how tokens with know values are encoded. This issue was fixed in version 20.0.380.92.

Sources

  • CVE.orgVulnerability recordCVE-2026-0809

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-0809

    30-day exploitation probability 0.29%

    first.org
  • EUVDVulnerability recordEUVD-2026-11567

    Use of a custom token encoding algorithm in Streamsoft Prestiż software allows the value of the KSeF (Krajowy System e-Faktur) token to be guessed after analyzing how tokens with know values are encoded. This issue was fixed in version 20.0.380.92.

    euvd.enisa.europa.eu
  • NIST NVDVulnerability recordCVE-2026-0809

    Use of a custom token encoding algorithm in Streamsoft Prestiż software allows the value of the KSeF (Krajowy System e-Faktur) token to be guessed after analyzing how tokens with know values are encoded. This issue was fixed in version 20.0.380.92.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 13, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • EUVDNov 8, 2026
  • FIRST EPSSNov 7, 2026
  • CVE.orgOct 16, 2026
  • NIST NVDOct 15, 2026