CVE-2026-45575Network attack vector

Signed authentication material theft via forged discovery document

Published May 26, 2026 · Updated May 26, 2026

Improper signature verification in Oviva AG epa4all-client before 1.2.2 allows man-in-the-middle attackers to capture signed authentication material. Before the patch, OidcClient consumed the IDP discovery document without OidcDiscoveryValidatorImpl and followed attacker-supplied key and authentication URLs. The attacker must intercept TLS inside the TI network; the client then encrypts the SMC-B-signed challenge response with the attacker's key and posts it to the attacker's endpoint.

CVSS severity7.4
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Oviva AG epa4all-client before 1.2.2 allows man-in-the-middle attackers to capture signed authentication material. Before the patch, OidcClient consumed the IDP discovery document without OidcDiscoveryValidatorImpl and followed attacker-supplied key and authentication URLs. The attacker must intercept TLS inside the TI network; the client then encrypts the SMC-B-signed challenge response with the attacker's key and posts it to the attacker's endpoint.

The record

CVE
CVE-2026-45575
Published
May 26, 2026
Updated
May 26, 2026
Vendor
Oviva AG
Product
epa4all-client
Classifications
CWE-347, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 26, 2026CVE publishedPublication date reported by the CVE source.
  2. May 26, 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=< 1.2.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oviva AG · epa4all-clientversion=< 1.2.2

Published CVSS scores

7.4GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A: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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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