---
id: "CVE-2026-117859"
kind: "vulnerability"
aliases: ["CVE-2026-117859"]
title: "Keycloak: restarted login flow lets a PAR request be reused"
severity: "medium"
cvss: 5.4
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["keycloak", "oauth", "package", "self-hosted"]
not_affected_if: ["par-not-used"]
published_at: "2026-10-29T07:16:44+00:00"
first_seen_at: "2026-10-29T07:23:29+00:00"
updated_at: "2026-10-29T07:23:46+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-117859", "first_seen_at": "2026-10-29T07:23:29+00:00"}]
---

# Keycloak: restarted login flow lets a PAR request be reused

Keycloak's Pushed Authorization Request (PAR) handling clears its single-use markers when an authentication flow restarts, while the request stays active. An attacker who holds the same authorization request can reuse it to obtain multiple access tokens.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-10-29T07:23:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-117859

## From the sources

A flaw was found in the Pushed Authorization Request PAR implementation of the keycloak-services component. The issue occurs when an authentication flow is restarted, which incorrectly clears the internal markers used to track PAR consumption while leaving the request active. This allows an attacker to reuse the same authorization request to obtain multiple access tokens, bypassing security requirements for single-use requests.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_