High Cross-site scripting

CVE-2026-65644 — Cross-site Scripting (XSS) in RocketChat Rocket.chat

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 has a REST API endpoint POST /api/v1/livechat/visitor that accepts an unauthenticated, unsanitized name field for Livechat visitors. This name is stored raw and later rendered via dangerouslySetInnerHTML in the Omnichannel Queue side panel (InquireSidePanelItem.tsx), injecting a real, clickable HTML link - pointing to any attacker-controlled domain, with arbitrary social-engineering text - into the DOM of any agent viewing the queue.

Published Aug 21, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database · CNA: support@hackerone.com

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

RocketChat

Rocket.chat

CVSS base

7.5

High · 1 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (RocketChat Rocket.chat).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (cross-site scripting), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
RocketChat	Rocket.chat	< 7.10.15≥ 8.1.0 and < 8.1.8≥ 8.2.0 and < 8.2.8≥ 8.3.0 and < 8.3.8≥ 8.4.0 and < 8.4.6≥ 8.5.0 and < 8.5.3≥ 8.6.0 and < 8.6.2version 8.7.0	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.5	CVSS 3.1	High	3.9	3.6	134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-79 · Cross-site Scripting (XSS)

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Monitor CSP violation reports and script payloads in reflected parameters.

web/proxy/WAF logsnetwork IDS/IPSapplication logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Fix documented
Oct 15, 2026 · NIST National Vulnerability Database
CVSS changed · 7.5
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Aug 21, 2026 · support@hackerone.com

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

2 on the record

github.com/RocketChat/Rocket.Chat/pull/41595
Patch, Vendor Advisory, NIST National Vulnerability Database
hackerone.com/reports/3872858
Third Party Advisory, Issue Tracking, NIST National Vulnerability Database

Elsewhere on this site

RocketChat
every CVE for this vendor

Cross-site scripting
same class

CWE-79
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-75575 Rocket.Chat Missing DDP Rate Limit on the sendForgotPasswordEmail Meteor Method Aug 24, 2026
Medium CVE-2026-65645 Improper Input Validation in RocketChat Rocket.chat Aug 21, 2026
Critical CVE-2026-58066 Improper Authentication in RocketChat Rocket.chat Jul 30, 2026
High CVE-2026-55762 Rocket.Chat: Any Authenticated User Can Permanently Deregister Workspace from Rocket.Chat Cloud via Unprotected `/api/v1/fingerprint` Endpoint Jun 24, 2026
High CVE-2026-55759 Rocket.Chat: Apple Sign-In skips JWT claims validation, allowing expired and cross-audience token replay Jun 24, 2026
Critical CVE-2026-55666 Rocket.Chat: improper authentication in Apple OAuth login (CVE-2026-55666) Jun 24, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No CISA SSVC assessment.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-65644 is "Cross-site Scripting (XSS) in RocketChat Rocket.chat", rated High. It affects Rocket.chat (RocketChat); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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