The vulnerability CVE-2026-63097 could compromise system integrity but typically requires user interaction to be exploited.
Status: Deferred
Published on: 17 Jul 2026, 16:17 UTC
CVSS Release: version 3
disclosure@vulncheck.com
Primary
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVE-2026-63097: Dendrite through 0.13.8 contains an improper access control vulnerability in the syncapi /context endpoint (syncapi/routing/context.go) that allows authenticated local users to access post-leave room state events by exploiting a flawed membership check that evaluates only the RoomExists field while ignoring IsInRoom, HasBeenInRoom, and Membership fields. Attackers who have left a room can call the rooms context API endpoint for a previously permitted event and receive unfiltered current room state that the /messages and /sync endpoints correctly withhold.
The exploitability of CVE-2026-63097 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2026-63097 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-63097, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-63097, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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