CVE-2026-97174
A flaw was found in the Client-Initiated Backchannel Authentication (CIBA) implementation of…
- Risk score
- 41/100
- CVSS
- 6.8 v3.1
- Published
- 5 Nov 2026
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What to know
- What it is
- A flaw was found in the Client-Initiated Backchannel Authentication (CIBA) implementation of Keycloak. The CIBA endpoint fails to properly validate the sub parameter, allowing it to be stored as an additional request parameter. During the token issuance process, this injected value overwrites the legitimate subject id…
- Affected
- See advisory
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 6.8 medium
References
Original description
A flaw was found in the Client-Initiated Backchannel Authentication (CIBA) implementation of Keycloak. The CIBA endpoint fails to properly validate the sub parameter, allowing it to be stored as an additional request parameter. During the token issuance process, this injected value overwrites the legitimate subject identifier. This allows an attacker to authenticate as themselves but receive security tokens belonging to a different victim user, leading to unauthorized account access.
Last activity 5 Nov 2026. Patch Forecast updates every hour.