CVE-2026-33875Network attack vector

Victim impersonation via malicious deep-link IdP relay

Published Mar 27, 2026 · Updated Mar 27, 2026

Authentication flow hijacking in gematik Authenticator before 4.16.0 allows remote attackers to impersonate users via malicious deep links. Missing deep-link input validation directs the application to an attacker-controlled IdP that relays traffic and intercepts intermediary token material. The attacker needs a valid client ID and redirect URI, and the victim must open the link and complete the authentication flow.

CVSS severity9.3
Critical
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication flow hijacking in gematik Authenticator before 4.16.0 allows remote attackers to impersonate users via malicious deep links. Missing deep-link input validation directs the application to an attacker-controlled IdP that relays traffic and intercepts intermediary token material. The attacker needs a valid client ID and redirect URI, and the victim must open the link and complete the authentication flow.

The record

CVE
CVE-2026-33875
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
gematik
Product
Authenticator
Classifications
CWE-940, T1557, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 27, 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=< 4.16.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

gematik · Authenticatorversion=< 4.16.0

Published CVSS scores

9.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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.

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

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-940Improper Verification of Source of a Communication Channel
T1557Adversary-in-the-Middle
T1204.001User Execution: Malicious Link

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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