{"id":"CVE-2026-0809","aliases":["EUVD-2026-11567","GHSA-4h75-v39v-9pq7"],"status":"published","title":"Weak KSeF token encoding in Streamsoft Prestiż","description":"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.\n\nThis issue was fixed in version 20.0.380.92.","severity":{"version":"4.0","score":6.3,"vector":"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","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-08","score":0.00291,"percentile":0.21864,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-261"],"published":"2026-03-12T13:02:24Z","modified":"2026-06-17T10:11:25Z","products":[{"vendor":"streamsoft","product":"streamsoft prestiż"}],"references":[{"url":"https://www.streamsoft.pl/streamsoft-prestiz/","tags":["product"]},{"url":"https://cert.pl/posts/2026/03/CVE-2026-0809","tags":["third-party-advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-0809"},{"url":"https://www.streamsoft.pl/streamsoft-prestiz"},{"url":"https://github.com/advisories/GHSA-4h75-v39v-9pq7"}],"sources":{"cve":[{"id":"CVE-2026-0809","title":"Weak KSeF token encoding in Streamsoft Prestiż","description":"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.\n\nThis issue was fixed in version 20.0.380.92.","status":"published","published":"2026-03-12T13:02:24.795Z","modified":"2026-03-12T14:04:53.073Z","cvss":[{"version":"4.0","score":6.3,"vector":"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","level":"medium","assessor":"cna"}],"cwes":["CWE-261"],"updated_at":"2026-11-02T14:20:13.587351Z"}],"euvd":[{"id":"EUVD-2026-11567","description":"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.\n\nThis issue was fixed in version 20.0.380.92.","status":"published","published":"2026-03-12T13:02:24Z","modified":"2026-03-12T14:04:53Z","cvss":[{"version":"4.0","score":6.3,"vector":"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","level":"medium"}],"updated_at":"2026-11-02T19:25:36.272941Z"}],"ghsa":[{"id":"GHSA-4h75-v39v-9pq7","title":"Use of a custom token encoding algorithm in Streamsoft Prestiż software allows the value of the...","description":"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.\n\nThis issue was fixed in version 20.0.380.92.","status":"published","published":"2026-03-12T15:30:25Z","modified":"2026-03-12T15:30:26Z","cvss":[{"version":"4.0","score":6.3,"vector":"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","level":"medium"}],"cwes":["CWE-261"],"updated_at":"2026-11-02T15:06:35.141921Z"}],"nvd":[{"id":"CVE-2026-0809","description":"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.\n\nThis issue was fixed in version 20.0.380.92.","status":"published","published":"2026-03-12T13:16:00.723Z","modified":"2026-06-17T10:11:25.173Z","cvss":[{"version":"4.0","score":6.3,"vector":"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","level":"medium","assessor":"secondary"}],"cwes":["CWE-261"],"updated_at":"2026-11-02T14:12:09.358914Z"}]}}