Improper input validation in Rocket.chat
CVE-2026-65645
Rocket.Chat in versions before 8.8.0, 8.7.1, 8.6.2, 8.5.3, 8.4.6. 8.3.8, 8.2.8, 8.1.8, and 7.10.15, the Meteor DDP methods getThreadsList and getThreadMessages accept rid / tmid as raw, untyped parameters with no schema validation. A MongoDB operator object (e.g. {"$gt": "4"}) can be substituted for a string room-id or message-id. The authorization check resolves to a room the attacker already has access to, while the downstream data query fans out across all rooms - disclosing private thread parents and their full reply content to any low-privilege authenticated user. The REST route chat.getThreadsList was patched in v5.0 (HackerOne report #1446767) by adding rid: {type:'string'} AJV validation. The equivalent DDP method was never given the same fix and remains exploitable
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (25.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 25.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Rocket.chat — versions 8.7.0
Weakness classification (CWE)
References
- hackerone.com/reports/3852135 (Third Party Advisory, Issue Tracking)
- github.com/RocketChat/Rocket.Chat/pull/41814 (Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-65645?
- CVE-2026-65645 is a medium-severity vulnerability in Rocket.chat, classified under Improper Input Validation. CVSS score: 4.3/10. Published 2026-08-21.
- How severe is CVE-2026-65645?
- Medium severity. CVSS v3 base score is 4.3 out of 10.