CVE-2026-9058Network attack vector

Authentication bypass via success status for untrusted chains

Published May 25, 2026 · Updated May 25, 2026

Certificate validation in Krajowa Izba Rozliczeniowa Szafir SDK before 1.8.463.2 allows remote attackers to impersonate users. Signature verification returns code 0 for cryptographically correct signatures even when the signer chain is untrusted, including certificates marked nondetermined or nonqualified. Authentication bypass requires an integrating application to accept that success code outside qualified-certificate authentication or to implement that use case incorrectly.

CVSS severity9.3
Critical
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Certificate validation in Krajowa Izba Rozliczeniowa Szafir SDK before 1.8.463.2 allows remote attackers to impersonate users. Signature verification returns code 0 for cryptographically correct signatures even when the signer chain is untrusted, including certificates marked nondetermined or nonqualified. Authentication bypass requires an integrating application to accept that success code outside qualified-certificate authentication or to implement that use case incorrectly.

The record

CVE
CVE-2026-9058
Published
May 25, 2026
Updated
May 25, 2026
Vendor
Krajowa Izba Rozliczeniowa S.A.
Product
Szafir SDK
Classifications
CWE-637, CWE-393, CWE-295, CAPEC-115, T1649
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2026CVE publishedPublication date reported by the CVE source.
  2. May 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <463

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Krajowa Izba Rozliczeniowa S.A. · Szafir SDKversion=0 <463

Published CVSS scores

9.3CERT PolskaCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-637Unnecessary Complexity in Protection Mechanism (Not Using 'Economy of Mechanism')
CWE-393Return of Wrong Status Code
CWE-295Improper Certificate Validation
CAPEC-115Authentication Bypass
T1649Steal or Forge Authentication Certificates

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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