# CVE-2026-124492: SunEditor before 3.4.0 Stored XSS via Link Modal Bookmark List

Status: published. Published: 2026-11-08. Updated: 2026-11-13.

SunEditor before 3.4.0 contains a stored cross-site scripting vulnerability in ModalAnchorEditor's #createBookmarkList, which inserts entity-decoded h1-h6 header textContent into the bookmark list via innerHTML without escaping. Attackers can store HTML-encoded payloads in editor headers that execute JavaScript when a victim opens the link modal and types # in the URL input.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- JiHong88 / suneditor: ≥ 0; < 3.4.0 (affected, semver); 3.4.0 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.3 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.6 (high); CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N; source: CNA: VulnCheck

- CVSS 4.0: 8.3 (high); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 7.6 (high); CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.21% as of 2026-11-12; percentile 11.51%

- SSVC: exploitation poc; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-79

## Exploit evidence

- exploit: https://github.com/JiHong88/suneditor/security/advisories/GHSA-5pp5-5qrp-vq56 (ADP: CISA-ADP)

## References

- https://github.com/JiHong88/suneditor/security/advisories/GHSA-5pp5-5qrp-vq56 (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/suneditor-before-3.4.0-stored-xss-via-link-modal-bookmark-list (CNA: VulnCheck; third-party-advisory)

- https://github.com/JiHong88/suneditor/security/advisories/GHSA-5pp5-5qrp-vq56 (ADP: CISA-ADP; exploit)

- https://github.com/JiHong88/suneditor/security/advisories/GHSA-5pp5-5qrp-vq56 (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/suneditor-before-3.4.0-stored-xss-via-link-modal-bookmark-list (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-124492; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-124492; retrieved 2026-11-13; source updated 2026-11-12

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-124492; retrieved 2026-11-13; source updated Not reported

Revision: 6edd75626aa37d956fff5d3015c449930e254fd8a22ebc13a98ba22ebf171a4a

Canonical: https://y2.dev/cve/CVE-2026-124492

## Agent and API access

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- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.