Typebot has Stored XSS via Rating Block Custom Icon that Bypasses isUnsafe Sandbox in Builder Preview
## Summary The rating block's custom icon feature accepts arbitrary HTML/SVG via the `customIcon.svg` field and renders it using Solid's `innerHTML` directive without any sanitization. When a malicious typebot is imported or crafted by a workspace collaborator, the payload executes in the builder's DOM context (builder.typebot.io), bypassing the `i...
CVSS 8.7 MEDIUM. SENTINEL APEX recommends immediate patch evaluation. Intelligence from 1 confirmed source(s).
๐ Executive Summary
This report analyzes CVE-2026-28445 affecting npm @typebot.io/js. Composite threat score: 49/100. Intelligence corroborated across 1 source(s): github_advisories. CVSS base score: 8.7. No confirmed in-the-wild exploitation at the time of writing; prioritize on exposure, privilege, and CVSS.
โ ๏ธ Business Impact Analysis
- โ ๏ธ Privilege escalation โ local attacker can become SYSTEM/root
๐ Representative Attack Path
A typical attack path for this vulnerability class, mapped to MITRE ATT&CK โ a representative model to guide detection and defense, not a claim of observed activity against a specific target. Confirm specifics against the primary sources below.
| # | Phase | Attacker Action | MITRE |
|---|---|---|---|
1 |
Reconnaissance | Attacker identifies exposed @typebot.io/js instances via Shodan, Censys, or targeted scanning | TA0043 |
2 |
Initial Access | Exploitation of CVE-2026-28445 in npm @typebot.io/js | T1190 |
3 |
Privilege Escalation | Local privilege escalation to SYSTEM/root for full control | T1068 |
4 |
Persistence | Backdoor, scheduled task, or new admin account created for persistent access | T1053 |
5 |
Command & Control | Attacker establishes persistent C2 channel using HTTPS or DNS tunneling | T1071 |
6 |
Impact / Objectives | Intellectual property theft, espionage, cryptomining, or preparation for future attack stage | T1657 |
โ Deep Dive Analysis
This high-severity vulnerability in npm @typebot.io/js (CVSS 8.7) represents a significant attack surface. SENTINEL APEX assesses exploitation to be technically feasible with moderate effort. Organizations running @typebot.io/js in internet-facing or privileged positions face immediate risk.
SENTINEL APEX URGENCY: HIGH. Score: 49/100 MEDIUM. Patch before exploitation activity begins.
๐ฏ MITRE ATT&CK Mapping
| Category | Mapping |
|---|---|
| Primary Tactic | Privilege Escalation |
| Primary Technique | T1068 โ Exploitation for Privilege Escalation |
| Sub-Technique | T1134 โ Access Token Manipulation |
| Weakness (CWE) | CWE-79 |
| Intel Type | ๐ด CVE ANALYSIS |
| Source(s) | github_advisories |
๐ด CVE Reference
| CVE ID | Reference | Score |
|---|---|---|
| CVE-2026-28445 | NVD โ | 8.7 |
| CVE-2026-28445 | NVD โ | 8.7 |
๐ท๏ธ Indicators of Compromise โ Enriched IOC Feed
Normalized IOCs with confidence scoring. Block immediately across all enforcement points. SOC Pro subscribers receive enriched IOC bundles with full attribution and STIX/TAXII feeds.
| Indicator Value | Type | Confidence | First Seen |
|---|---|---|---|
| builder.typebot.io | domain | 75% | 2026-05-26 |
๐ Detection Rules โ Sigma (SIEM)
Deploy to Splunk, Elastic, Microsoft Sentinel, or QRadar. SOC Pro subscribers receive pre-compiled SIEM-native query packs updated with each pipeline run.
๐ก Detection Rules โ YARA (Endpoint)
Deploy to endpoint detection platforms. Enterprise subscribers receive tuned, FP-validated YARA rule packs.
๐ก๏ธ SOC Response Playbook
- 1IMMEDIATE (0-1hr): Identify all instances of @typebot.io/js in your environment via CMDB/asset inventory
- 2IMMEDIATE: Block all 1 IOCs in this report at firewall, proxy, DNS, and EDR simultaneously
- 3IMMEDIATE (0-1hr): Apply vendor patch โ no maintenance window exception for MEDIUM threats
- 4IMMEDIATE (1-2hr): If no patch available: implement WAF rules, ACLs, or network-level compensating controls
- 5SHORT-TERM (2-4hr): Deploy Sigma detection rule to SIEM โ validate alert generation in test environment
- 6SHORT-TERM (4-8hr): Review logs for exploitation indicators (anomalous @typebot.io/js requests, error spikes)
- 7SHORT-TERM (8-24hr): Hunt for post-exploitation: new admin accounts, scheduled tasks, lateral movement
- 8MONITOR: Subscribe to npm security advisories for patch updates
- 9ONGOING: Track SENTINEL APEX intelligence feed for follow-on campaigns targeting @typebot.io/js
๐ Intelligence References
- github.com/advisories/GHSA-6m7c-xfhp-p9fh
- github.com/baptisteArno/typebot.io/security/advisories/GHSA-6m7c-xfhp-
- nvd.nist.gov/vuln/detail/CVE-2026-28445
- github.com/baptisteArno/typebot.io/commit/474ecbf46bc47a75265bada2599f
- github.com/baptisteArno/typebot.io/blob/v3.16.0/packages/embeds/js/pac
- ๐ NVD โ CVE-2026-28445
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Report ID: SENTINEL-CVE-2026-28445-2026-05-26 | Priority: 49/100 MEDIUM | Sources: 1
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