CVE-2026-0809

MEDIUMNVD 6.36.3—

6.3

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.

CVSS v3: 6.3
EG Score: 6.3(medium)
EPSS: 19.3%
KEV: Not listed

Published

March 12, 2026

Last Modified

April 27, 2026

References (2)

cvd@certhttps://cert.pl/posts/2026/03/CVE-2026-0809
cvd@certhttps://www.streamsoft.pl/streamsoft-prestiz/

Data Freshness Timeline

(refreshed 18× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

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2026-05-23 00:09 UTCEG score recompute
2026-05-22 21:16 UTCepss_batch

Frequently asked(5)

What is CVE-2026-0809?

CVE-2026-0809 is a medium vulnerability published on March 12, 2026. 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.

When was CVE-2026-0809 disclosed?

CVE-2026-0809 was first published in the National Vulnerability Database on March 12, 2026, with the most recent update on April 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2026-0809 actively exploited?

CVE-2026-0809 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 19.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2026-0809?

CVE-2026-0809 has a CVSS v3 base score of 6.3 (NVD).

How do I remediate CVE-2026-0809?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-0809, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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CVE-2026-0809

📅 Published

🔄 Last Modified

🔗 References (2)