9.3
CRITICAL CVSS 4.0
CVE-2026-9058
Improper Certificate Verification in Szafir SDK
Description

Szafir SDK returns a success status code from the cryptographic digital signature verification process (i.e. /VerifyingTaskItem/Signature/VerificationResult/Result/@code == 0, "Positively verified") even when the trust status of the signer's certificate could not be established (i.e. /VerifyingTaskItem/Signature/VerificationResult/SigningCertificate/@certificateType == "nondetermined"). This causes consuming applications to incorrectly treat the signature as valid despite an unverified certificate chain, enabling authentication bypass and user impersonation. This issue was fixed in version 463.

INFO

Published Date :

May 25, 2026, 1:23 p.m.

Last Modified :

May 25, 2026, 1:23 p.m.

Remotely Exploit :

Yes !

Source :

CERT-PL
Affected Products

The following products are affected by CVE-2026-9058 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 CRITICAL 4bb8329e-dd38-46c1-aafb-9bf32bcb93c6
Solution
Update Szafir SDK to version 463 or later to fix signature verification issues.
  • Update Szafir SDK to version 463 or later.
  • Ensure certificate trust is properly validated.
  • Verify signature validity using established trust.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-9058 vulnerability anywhere in the article.

  • cert.pl
Vulnerability in Szafir SDK software

Vulnerability in Szafir SDK software CVE ID CVE-2026-9058 Publication date 25 May 2026 Vendor Krajowa Izba Rozliczeniowa Product Szafir SDK Vulnerable versions All before 463 Vulnerability type (CWE) ... Read more

Published Date: May 25, 2026 (4 hours, 2 minutes ago)

The following table lists the changes that have been made to the CVE-2026-9058 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    May. 25, 2026

    Action Type Old Value New Value
    Added Description Szafir SDK returns a success status code from the cryptographic digital signature verification process (i.e. /VerifyingTaskItem/Signature/VerificationResult/Result/@code == 0, "Positively verified") even when the trust status of the signer's certificate could not be established (i.e. /VerifyingTaskItem/Signature/VerificationResult/SigningCertificate/@certificateType == "nondetermined"). This causes consuming applications to incorrectly treat the signature as valid despite an unverified certificate chain, enabling authentication bypass and user impersonation. This issue was fixed in version 463.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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
    Added CWE CWE-393
    Added CWE CWE-637
    Added Reference https://cert.pl/posts/2026/05/CVE-2026-9058
    Added Reference https://www.elektronicznypodpis.pl/
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.