CVE-2026-0809 json
Weak KSeF token encoding in Streamsoft Prestiż
published 7mo ago modified 4mo ago also EUVD-2026-11567
- cvss
- 6.3
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 21%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Streamsoft Streamsoft Prestiż 20.0.380.92
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 7mo ago
Exploit prediction
0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N |
| CNA | 4.0 | 6.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- Streamsoft Streamsoft Prestiż
Classification
- Weakness
-
- CWE-261 Weak Encoding for Password
References
-
streamsoft.pl
/streamsoft-prestiz/
product
-
cert.pl
/posts/2026/03/CVE-2026-0809
third-party-advisory
Sources
- CVE List CVE-2026-0809
- NVD CVE-2026-0809
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